org.scalactic.anyvals.NonEmptyList.scala Maven / Gradle / Ivy
/*
* Copyright 2001-2013 Artima, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.scalactic.anyvals
import scala.annotation.unchecked.{ uncheckedVariance => uV }
import scala.collection.GenIterable
import scala.collection.GenSeq
import scala.collection.GenTraversableOnce
import scala.collection.generic.CanBuildFrom
import scala.collection.mutable.Buffer
import scala.reflect.ClassTag
import scala.collection.immutable
import scala.collection.mutable.ArrayBuffer
import org.scalactic.Every
// Can't be a LinearSeq[T] because Builder would be able to create an empty one.
/**
* A non-empty list: an ordered, immutable, non-empty collection of elements with LinearSeq
performance characteristics.
*
*
* The purpose of NonEmptyList
is to allow you to express in a type that a List
is non-empty, thereby eliminating the
* need for (and potential exception from) a run-time check for non-emptiness. For a non-empty sequence with IndexedSeq
* performance, see Every
.
*
*
* Constructing NonEmptyList
s
*
*
* You can construct a NonEmptyList
by passing one or more elements to the NonEmptyList.apply
factory method:
*
*
*
* scala> NonEmptyList(1, 2, 3)
* res0: org.scalactic.anyvals.NonEmptyList[Int] = NonEmptyList(1, 2, 3)
*
*
*
* Alternatively you can cons elements onto the End
singleton object, similar to making a List
starting with Nil
:
*
*
*
* scala> 1 :: 2 :: 3 :: Nil
* res0: List[Int] = List(1, 2, 3)
*
* scala> 1 :: 2 :: 3 :: End
* res1: org.scalactic.NonEmptyList[Int] = NonEmptyList(1, 2, 3)
*
*
*
* Note that although Nil
is a List[Nothing]
, End
is
* not a NonEmptyList[Nothing]
, because no empty NonEmptyList
exists. (A non-empty list is a series
* of connected links; if you have no links, you have no non-empty list.)
*
*
*
* scala> val nil: List[Nothing] = Nil
* nil: List[Nothing] = List()
*
* scala> val nada: NonEmptyList[Nothing] = End
* <console>:16: error: type mismatch;
* found : org.scalactic.anyvals.End.type
* required: org.scalactic.anyvals.NonEmptyList[Nothing]
* val nada: NonEmptyList[Nothing] = End
* ^
*
*
* Working with NonEmptyList
s
*
*
* NonEmptyList
does not extend Scala's Seq
or Traversable
traits because these require that
* implementations may be empty. For example, if you invoke tail
on a Seq
that contains just one element,
* you'll get an empty Seq
:
*
*
*
* scala> List(1).tail
* res6: List[Int] = List()
*
*
*
* On the other hand, many useful methods exist on Seq
that when invoked on a non-empty Seq
are guaranteed
* to not result in an empty Seq
. For convenience, NonEmptyList
defines a method corresponding to every such Seq
* method. Here are some examples:
*
*
*
* NonEmptyList(1, 2, 3).map(_ + 1) // Result: NonEmptyList(2, 3, 4)
* NonEmptyList(1).map(_ + 1) // Result: NonEmptyList(2)
* NonEmptyList(1, 2, 3).containsSlice(NonEmptyList(2, 3)) // Result: true
* NonEmptyList(1, 2, 3).containsSlice(NonEmptyList(3, 4)) // Result: false
* NonEmptyList(-1, -2, 3, 4, 5).minBy(_.abs) // Result: -1
*
*
*
* NonEmptyList
does not currently define any methods corresponding to Seq
methods that could result in
* an empty Seq
. However, an implicit converison from NonEmptyList
to List
* is defined in the NonEmptyList
companion object that will be applied if you attempt to call one of the missing methods. As a
* result, you can invoke filter
on an NonEmptyList
, even though filter
could result
* in an empty sequence—but the result type will be List
instead of NonEmptyList
:
*
*
*
* NonEmptyList(1, 2, 3).filter(_ < 10) // Result: List(1, 2, 3)
* NonEmptyList(1, 2, 3).filter(_ > 10) // Result: List()
*
*
*
*
* You can use NonEmptyList
s in for
expressions. The result will be an NonEmptyList
unless
* you use a filter (an if
clause). Because filters are desugared to invocations of filter
, the
* result type will switch to a List
at that point. Here are some examples:
*
*
*
* scala> import org.scalactic.anyvals._
* import org.scalactic.anyvals._
*
* scala> for (i <- NonEmptyList(1, 2, 3)) yield i + 1
* res0: org.scalactic.anyvals.NonEmptyList[Int] = NonEmptyList(2, 3, 4)
*
* scala> for (i <- NonEmptyList(1, 2, 3) if i < 10) yield i + 1
* res1: List[Int] = List(2, 3, 4)
*
* scala> for {
* | i <- NonEmptyList(1, 2, 3)
* | j <- NonEmptyList('a', 'b', 'c')
* | } yield (i, j)
* res3: org.scalactic.anyvals.NonEmptyList[(Int, Char)] =
* NonEmptyList((1,a), (1,b), (1,c), (2,a), (2,b), (2,c), (3,a), (3,b), (3,c))
*
* scala> for {
* | i <- NonEmptyList(1, 2, 3) if i < 10
* | j <- NonEmptyList('a', 'b', 'c')
* | } yield (i, j)
* res6: List[(Int, Char)] =
* List((1,a), (1,b), (1,c), (2,a), (2,b), (2,c), (3,a), (3,b), (3,c))
*
*
* @tparam T the type of elements contained in this NonEmptyList
*/
final class NonEmptyList[+T] private (val toList: List[T]) extends AnyVal {
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed NonEmptyList
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this and the passed NonEmptyList
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the NonEmptyList
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def ++[U >: T](other: NonEmptyList[U]): NonEmptyList[U] = new NonEmptyList(toList ++ other.toList)
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed Every
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this NonEmptyList
and the passed Every
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the Every
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def ++[U >: T](other: Every[U]): NonEmptyList[U] = new NonEmptyList(toList ++ other.toVector)
// TODO: Have I added these extra ++, etc. methods to Every that take a NonEmptyList?
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed GenTraversableOnce
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this NonEmptyList
* and the passed GenTraversableOnce
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the GenTraversableOnce
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def ++[U >: T](other: org.scalactic.ColCompatHelper.IterableOnce[U]): NonEmptyList[U] =
if (other.isEmpty) this else new NonEmptyList(toList ++ other.toStream)
/**
* The /:
method has been deprecated and will be removed in a future version of Scalactic. Please use
* foldLeft
instead.
*
* This method has been deprecated for consistency with Scala 2.13's collections API.
*
*
* Fold left: applies a binary operator to a start value, z
, and all elements of this NonEmptyList
, going left to right.
*
*
*
* Note: /:
is alternate syntax for the foldLeft
method; z
/:
non-empty list
is the
* same as non-empty list
foldLeft
z
.
*
*
* @tparam B the result of the binary operator
* @param z the start value
* @param op the binary operator
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going left to right, with the start value,
* z
, on the left:
*
*
* op(...op(op(z, x_1), x_2), ..., x_n)
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
@deprecated("The /: method has been deprecated and will be removed in a future version of Scalactic. Please use foldLeft instead.", "3.1.x")
final def /:[B](z: B)(op: (B, T) => B): B = toList./:(z)(op)
/**
* The :\\
method has been deprecated and will be removed in a future version of Scalactic. Please use
* foldRight
instead.
*
* This method has been deprecated for consistency with Scala 2.13's collections API.
*
* Fold right: applies a binary operator to all elements of this NonEmptyList
and a start value, going right to left.
*
*
* Note: :\
is alternate syntax for the foldRight
method; non-empty list
:\
z
is the same
* as non-empty list
foldRight
z
.
*
*
* @tparam B the result of the binary operator
* @param z the start value
* @param op the binary operator
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going right to left, with the start value,
* z
, on the right:
*
*
* op(x_1, op(x_2, ... op(x_n, z)...))
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
@deprecated("The :\\ method has been deprecated and will be removed in a future version of Scalactic. Please use foldRight instead.", "3.1.x")
final def :\[B](z: B)(op: (T, B) => B): B = toList.:\(z)(op)
/**
* Returns a new NonEmptyList
with the given element prepended.
*
*
* Note that :-ending operators are right associative. A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
*
*
* @param element the element to prepend to this NonEmptyList
* @return a new NonEmptyList
consisting of element
followed by all elements of this NonEmptyList
.
*/
final def +:[U >: T](element: U): NonEmptyList[U] = new NonEmptyList(element +: toList)
/**
* Adds an element to the beginning of this NonEmptyList
.
*
*
* Note that :-ending operators are right associative. A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
*
*
* @param element the element to prepend to this NonEmptyList
* @return a NonEmptyList
that contains element
as first element and that continues with this NonEmptyList
.
*/
final def ::[U >: T](element: U): NonEmptyList[U] = new NonEmptyList(element +: toList)
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed NonEmptyList
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this and the passed NonEmptyList
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the NonEmptyList
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def :::[U >: T](other: NonEmptyList[U]): NonEmptyList[U] = new NonEmptyList(other.toList ::: toList)
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed Every
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this and the passed Every
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the Every
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def :::[U >: T](other: Every[U]): NonEmptyList[U] = new NonEmptyList(other.toList ::: toList)
/**
* Returns a new NonEmptyList
containing the elements of this NonEmptyList
followed by the elements of the passed GenTraversableOnce
.
* The element type of the resulting NonEmptyList
is the most specific superclass encompassing the element types of this NonEmptyList
* and the passed GenTraversableOnce
.
*
* @tparam U the element type of the returned NonEmptyList
* @param other the GenTraversableOnce
to append
* @return a new NonEmptyList
that contains all the elements of this NonEmptyList
followed by all elements of other
.
*/
def :::[U >: T](other: GenTraversableOnce[U]): NonEmptyList[U] =
if (other.isEmpty) this else new NonEmptyList(other.toList ::: toList)
/**
* Returns a new NonEmptyList
with the given element appended.
*
*
* Note a mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
*
*
* @param element the element to append to this NonEmptyList
* @return a new NonEmptyList
consisting of all elements of this NonEmptyList
followed by element
.
*/
def :+[U >: T](element: U): NonEmptyList[U] = new NonEmptyList(toList :+ element)
/**
* Appends all elements of this NonEmptyList
to a string builder. The written text will consist of a concatenation of the result of invoking toString
* on of every element of this NonEmptyList
, without any separator string.
*
* @param sb the string builder to which elements will be appended
* @return the string builder, sb
, to which elements were appended.
*/
final def addString(sb: StringBuilder): StringBuilder = toList.addString(sb)
/**
* Appends all elements of this NonEmptyList
to a string builder using a separator string. The written text will consist of a concatenation of the
* result of invoking toString
* on of every element of this NonEmptyList
, separated by the string sep
.
*
* @param sb the string builder to which elements will be appended
* @param sep the separator string
* @return the string builder, sb
, to which elements were appended.
*/
final def addString(sb: StringBuilder, sep: String): StringBuilder = toList.addString(sb, sep)
/**
* Appends all elements of this NonEmptyList
to a string builder using start, end, and separator strings. The written text will consist of a concatenation of
* the string start
; the result of invoking toString
on all elements of this NonEmptyList
,
* separated by the string sep
; and the string end
*
* @param sb the string builder to which elements will be appended
* @param start the starting string
* @param sep the separator string
* @param start the ending string
* @return the string builder, sb
, to which elements were appended.
*/
final def addString(sb: StringBuilder, start: String, sep: String, end: String): StringBuilder = toList.addString(sb, start, sep, end)
/**
* Selects an element by its index in the NonEmptyList
.
*
* @return the element of this NonEmptyList
at index idx
, where 0 indicates the first element.
*/
final def apply(idx: Int): T = toList(idx)
/**
* Finds the first element of this NonEmptyList
for which the given partial function is defined, if any, and applies the partial function to it.
*
* @param pf the partial function
* @return an Option
containing pf
applied to the first element for which it is defined, or None
if
* the partial function was not defined for any element.
*/
final def collectFirst[U](pf: PartialFunction[T, U]): Option[U] = toList.collectFirst(pf)
/**
* Indicates whether this NonEmptyList
contains a given value as an element.
*
* @param elem the element to look for
* @return true if this NonEmptyList
has an element that is equal (as determined by ==)
to elem
, false otherwise.
*/
final def contains(elem: Any): Boolean = toList.contains(elem)
/**
* Indicates whether this NonEmptyList
contains a given GenSeq
as a slice.
*
* @param that the GenSeq
slice to look for
* @return true if this NonEmptyList
contains a slice with the same elements as that
, otherwise false
.
*/
final def containsSlice[B](that: GenSeq[B]): Boolean = toList.containsSlice(that)
/**
* Indicates whether this NonEmptyList
contains a given Every
as a slice.
*
* @param that the Every
slice to look for
* @return true if this NonEmptyList
contains a slice with the same elements as that
, otherwise false
.
*/
final def containsSlice[B](that: Every[B]): Boolean = toList.containsSlice(that.toVector)
/**
* Indicates whether this NonEmptyList
contains a given NonEmptyList
as a slice.
*
* @param that the NonEmptyList
slice to look for
* @return true if this NonEmptyList
contains a slice with the same elements as that
, otherwise false
.
*/
final def containsSlice[B](that: NonEmptyList[B]): Boolean = toList.containsSlice(that.toList)
/**
* Copies values of this NonEmptyList
to an array. Fills the given array arr
with values of this NonEmptyList
. Copying
* will stop once either the end of the current NonEmptyList
is reached, or the end of the array is reached.
*
* @param arr the array to fill
*/
final def copyToArray[U >: T](arr: Array[U]): Unit = toList.copyToArray(arr)
/**
* Copies values of this NonEmptyList
to an array. Fills the given array arr
with values of this NonEmptyList
, beginning at
* index start
. Copying will stop once either the end of the current NonEmptyList
is reached, or the end of the array is reached.
*
* @param arr the array to fill
* @param start the starting index
*/
final def copyToArray[U >: T](arr: Array[U], start: Int): Unit = toList.copyToArray(arr, start)
/**
* Copies values of this NonEmptyList
to an array. Fills the given array arr
with at most len
elements of this NonEmptyList
, beginning at
* index start
. Copying will stop once either the end of the current NonEmptyList
is reached, the end of the array is reached, or
* len
elements have been copied.
*
* @param arr the array to fill
* @param start the starting index
* @param len the maximum number of elements to copy
*/
final def copyToArray[U >: T](arr: Array[U], start: Int, len: Int): Unit = toList.copyToArray(arr, start, len)
/**
* Copies all elements of this NonEmptyList
to a buffer.
*
* @param buf the buffer to which elements are copied
*/
final def copyToBuffer[U >: T](buf: Buffer[U]): Unit = toList.copyToBuffer(buf)
/**
* Indicates whether every element of this NonEmptyList
relates to the corresponding element of a given GenSeq
by satisfying a given predicate.
*
* @tparam B the type of the elements of that
* @param that the GenSeq
to compare for correspondence
* @param p the predicate, which relates elements from this NonEmptyList
and the passed GenSeq
* @return true if this NonEmptyList
and the passed GenSeq
have the same length and p(x, y)
is true
* for all corresponding elements x
of this NonEmptyList
and y
of that, otherwise false
.
*/
final def corresponds[B](that: GenSeq[B])(p: (T, B) => Boolean): Boolean = toList.corresponds(that)(p)
/**
* Indicates whether every element of this NonEmptyList
relates to the corresponding element of a given Every
by satisfying a given predicate.
*
* @tparam B the type of the elements of that
* @param that the Every
to compare for correspondence
* @param p the predicate, which relates elements from this NonEmptyList
and the passed Every
* @return true if this NonEmptyList
and the passed Every
have the same length and p(x, y)
is true
* for all corresponding elements x
of this NonEmptyList
and y
of that, otherwise false
.
*/
final def corresponds[B](that: Every[B])(p: (T, B) => Boolean): Boolean = toList.corresponds(that.toVector)(p)
/**
* Indicates whether every element of this NonEmptyList
relates to the corresponding element of a given NonEmptyList
by satisfying a given predicate.
*
* @tparam B the type of the elements of that
* @param that the NonEmptyList
to compare for correspondence
* @param p the predicate, which relates elements from this and the passed NonEmptyList
* @return true if this and the passed NonEmptyList
have the same length and p(x, y)
is true
* for all corresponding elements x
of this NonEmptyList
and y
of that, otherwise false
.
*/
final def corresponds[B](that: NonEmptyList[B])(p: (T, B) => Boolean): Boolean = toList.corresponds(that.toList)(p)
/**
* Counts the number of elements in this NonEmptyList
that satisfy a predicate.
*
* @param p the predicate used to test elements.
* @return the number of elements satisfying the predicate p
.
*/
final def count(p: T => Boolean): Int = toList.count(p)
/**
* Builds a new NonEmptyList
from this NonEmptyList
without any duplicate elements.
*
* @return A new NonEmptyList
that contains the first occurrence of every element of this NonEmptyList
.
*/
final def distinct: NonEmptyList[T] = new NonEmptyList(toList.distinct)
/**
* Indicates whether this NonEmptyList
ends with the given GenSeq
.
*
* @param that the sequence to test
* @return true
if this NonEmptyList
has that
as a suffix, false
otherwise.
*/
final def endsWith[B](that: GenSeq[B]): Boolean = toList.endsWith(that)
/**
* Indicates whether this NonEmptyList
ends with the given Every
.
*
* @param that the Every
to test
* @return true
if this NonEmptyList
has that
as a suffix, false
otherwise.
*/
final def endsWith[B](that: Every[B]): Boolean = toList.endsWith(that.toVector)
// TODO: Search for that: Every in here and add a that: NonEmptyList in Every.
/**
* Indicates whether this NonEmptyList
ends with the given NonEmptyList
.
*
* @param that the NonEmptyList
to test
* @return true
if this NonEmptyList
has that
as a suffix, false
otherwise.
*/
final def endsWith[B](that: NonEmptyList[B]): Boolean = toList.endsWith(that.toList)
/*
override def equals(o: Any): Boolean =
o match {
case nonEmptyList: NonEmptyList[_] => toList == nonEmptyList.toList
case _ => false
}
*/
/**
* Indicates whether a predicate holds for at least one of the elements of this NonEmptyList
.
*
* @param the predicate used to test elements.
* @return true
if the given predicate p
holds for some of the elements of this NonEmptyList
, otherwise false
.
*/
final def exists(p: T => Boolean): Boolean = toList.exists(p)
/**
* Finds the first element of this NonEmptyList
that satisfies the given predicate, if any.
*
* @param p the predicate used to test elements
* @return an Some
containing the first element in this NonEmptyList
that satisfies p
, or None
if none exists.
*/
final def find(p: T => Boolean): Option[T] = toList.find(p)
/**
* Builds a new NonEmptyList
by applying a function to all elements of this NonEmptyList
and using the elements of the resulting NonEmptyList
s.
*
* @tparam U the element type of the returned NonEmptyList
* @param f the function to apply to each element.
* @return a new NonEmptyList
containing elements obtained by applying the given function f
to each element of this NonEmptyList
and concatenating
* the elements of resulting NonEmptyList
s.
*/
final def flatMap[U](f: T => NonEmptyList[U]): NonEmptyList[U] = {
val buf = new ArrayBuffer[U]
for (ele <- toList)
buf ++= f(ele).toList
new NonEmptyList(buf.toList)
}
/**
* Converts this NonEmptyList
of NonEmptyList
s into a NonEmptyList
* formed by the elements of the nested NonEmptyList
s.
*
*
* Note: You cannot use this flatten
method on a NonEmptyList
that contains a GenTraversableOnce
s, because
* if all the nested GenTraversableOnce
s were empty, you'd end up with an empty NonEmptyList
.
*
*
* @tparm B the type of the elements of each nested NonEmptyList
* @return a new NonEmptyList
resulting from concatenating all nested NonEmptyList
s.
*/
final def flatten[B](implicit ev: T <:< NonEmptyList[B]): NonEmptyList[B] = flatMap(ev)
/**
* Folds the elements of this NonEmptyList
using the specified associative binary operator.
*
*
* The order in which operations are performed on elements is unspecified and may be nondeterministic.
*
*
* @tparam U a type parameter for the binary operator, a supertype of T.
* @param z a neutral element for the fold operation; may be added to the result an arbitrary number of
* times, and must not change the result (e.g., Nil
for list concatenation,
* 0 for addition, or 1 for multiplication.)
* @param op a binary operator that must be associative
* @return the result of applying fold operator op
between all the elements and z
*/
final def fold[U >: T](z: U)(op: (U, U) => U): U = toList.fold(z)(op)
/**
* Applies a binary operator to a start value and all elements of this NonEmptyList
, going left to right.
*
* @tparam B the result type of the binary operator.
* @param z the start value.
* @param op the binary operator.
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going left to right, with the start value,
* z
, on the left:
*
*
* op(...op(op(z, x_1), x_2), ..., x_n)
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
final def foldLeft[B](z: B)(op: (B, T) => B): B = toList.foldLeft(z)(op)
/**
* Applies a binary operator to all elements of this NonEmptyList
and a start value, going right to left.
*
* @tparam B the result of the binary operator
* @param z the start value
* @param op the binary operator
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going right to left, with the start value,
* z
, on the right:
*
*
* op(x_1, op(x_2, ... op(x_n, z)...))
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
final def foldRight[B](z: B)(op: (T, B) => B): B = toList.foldRight(z)(op)
/**
* Indicates whether a predicate holds for all elements of this NonEmptyList
.
*
* @param p the predicate used to test elements.
* @return true
if the given predicate p
holds for all elements of this NonEmptyList
, otherwise false
.
*/
final def forall(p: T => Boolean): Boolean = toList.forall(p)
/**
* Applies a function f
to all elements of this NonEmptyList
.
*
* @param f the function that is applied for its side-effect to every element. The result of function f
is discarded.
*/
final def foreach(f: T => Unit): Unit = toList.foreach(f)
/**
* Partitions this NonEmptyList
into a map of NonEmptyList
s according to some discriminator function.
*
* @tparam K the type of keys returned by the discriminator function.
* @param f the discriminator function.
* @return A map from keys to NonEmptyList
s such that the following invariant holds:
*
*
* (nonEmptyList.toList partition f)(k) = xs filter (x => f(x) == k)
*
*
*
* That is, every key k
is bound to a NonEmptyList
of those elements x
for which f(x)
equals k
.
*
*/
final def groupBy[K](f: T => K): Map[K, NonEmptyList[T]] = {
val mapKToList = toList.groupBy(f)
mapKToList.mapValues { list => new NonEmptyList(list) }.toMap
}
/**
* Partitions elements into fixed size NonEmptyList
s.
*
* @param size the number of elements per group
* @return An iterator producing NonEmptyList
s of size size
, except the last will be truncated if the elements don't divide evenly.
*/
final def grouped(size: Int): Iterator[NonEmptyList[T]] = {
val itOfList = toList.grouped(size)
itOfList.map { list => new NonEmptyList(list) }
}
/**
* Returns true
to indicate this NonEmptyList
has a definite size, since all NonEmptyList
s are strict collections.
*/
final def hasDefiniteSize: Boolean = true
// override def hashCode: Int = toList.hashCode
/**
* Selects the first element of this NonEmptyList
.
*
* @return the first element of this NonEmptyList
.
*/
final def head: T = toList.head
// Methods like headOption I can't get rid of because of the implicit conversion to GenTraversable.
// Users can call any of the methods I've left out on a NonEmptyList, and get whatever List would return
// for that method call. Eventually I'll probably implement them all to save the implicit conversion.
/**
* Selects the first element of this NonEmptyList
and returns it wrapped in a Some
.
*
* @return the first element of this NonEmptyList
, wrapped in a Some
.
*/
final def headOption: Option[T] = toList.headOption
/**
* Finds index of first occurrence of some value in this NonEmptyList
.
*
* @param elem the element value to search for.
* @return the index of the first element of this NonEmptyList
that is equal (as determined by ==
) to elem
,
* or -1
, if none exists.
*/
final def indexOf[U >: T](elem: U): Int = toList.indexOf(elem, 0)
/**
* Finds index of first occurrence of some value in this NonEmptyList
after or at some start index.
*
* @param elem the element value to search for.
* @param from the start index
* @return the index >=
from
of the first element of this NonEmptyList
that is equal (as determined by ==
) to elem
,
* or -1
, if none exists.
*/
final def indexOf[U >: T](elem: U, from: Int): Int = toList.indexOf(elem, from)
/**
* Finds first index where this NonEmptyList
contains a given GenSeq
as a slice.
*
* @param that the GenSeq
defining the slice to look for
* @return the first index at which the elements of this NonEmptyList
starting at that index match the elements of
* GenSeq
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: GenSeq[U]): Int = toList.indexOfSlice(that)
/**
* Finds first index after or at a start index where this NonEmptyList
contains a given GenSeq
as a slice.
*
* @param that the GenSeq
defining the slice to look for
* @param from the start index
* @return the first index >=
from
at which the elements of this NonEmptyList
starting at that index match the elements of
* GenSeq
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: GenSeq[U], from: Int): Int = toList.indexOfSlice(that, from)
/**
* Finds first index where this NonEmptyList
contains a given Every
as a slice.
*
* @param that the Every
defining the slice to look for
* @return the first index such that the elements of this NonEmptyList
starting at this index match the elements of
* Every
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: Every[U]): Int = toList.indexOfSlice(that.toVector)
/**
* Finds first index where this NonEmptyList
contains a given NonEmptyList
as a slice.
*
* @param that the NonEmptyList
defining the slice to look for
* @return the first index such that the elements of this NonEmptyList
starting at this index match the elements of
* NonEmptyList
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: NonEmptyList[U]): Int = toList.indexOfSlice(that.toList)
/**
* Finds first index after or at a start index where this NonEmptyList
contains a given Every
as a slice.
*
* @param that the Every
defining the slice to look for
* @param from the start index
* @return the first index >=
from
such that the elements of this NonEmptyList
starting at this index match the elements of
* Every
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: Every[U], from: Int): Int = toList.indexOfSlice(that.toVector, from)
/**
* Finds first index after or at a start index where this NonEmptyList
contains a given NonEmptyList
as a slice.
*
* @param that the NonEmptyList
defining the slice to look for
* @param from the start index
* @return the first index >=
from
such that the elements of this NonEmptyList
starting at this index match the elements of
* NonEmptyList
that
, or -1
of no such subsequence exists.
*/
final def indexOfSlice[U >: T](that: NonEmptyList[U], from: Int): Int = toList.indexOfSlice(that.toList, from)
/**
* Finds index of the first element satisfying some predicate.
*
* @param p the predicate used to test elements.
* @return the index of the first element of this NonEmptyList
that satisfies the predicate p
,
* or -1
, if none exists.
*/
final def indexWhere(p: T => Boolean): Int = toList.indexWhere(p)
/**
* Finds index of the first element satisfying some predicate after or at some start index.
*
* @param p the predicate used to test elements.
* @param from the start index
* @return the index >=
from
of the first element of this NonEmptyList
that satisfies the predicate p
,
* or -1
, if none exists.
*/
final def indexWhere(p: T => Boolean, from: Int): Int = toList.indexWhere(p, from)
/**
* Produces the range of all indices of this NonEmptyList
.
*
* @return a Range
value from 0
to one less than the length of this NonEmptyList
.
*/
final def indices: Range = toList.indices
/**
* Tests whether this NonEmptyList
contains given index.
*
* @param idx the index to test
* @return true if this NonEmptyList
contains an element at position idx
, false
otherwise.
*/
final def isDefinedAt(idx: Int): Boolean = toList.isDefinedAt(idx)
/**
* Returns false
to indicate this NonEmptyList
, like all NonEmptyList
s, is non-empty.
*
* @return false
*/
final def isEmpty: Boolean = false
/**
* Returns true
to indicate this NonEmptyList
, like all NonEmptyList
s, can be traversed repeatedly.
*
* @return true
*/
final def isTraversableAgain: Boolean = true
/**
* Creates and returns a new iterator over all elements contained in this NonEmptyList
.
*
* @return the new iterator
*/
final def iterator: Iterator[T] = toList.iterator
/**
* Selects the last element of this NonEmptyList
.
*
* @return the last element of this NonEmptyList
.
*/
final def last: T = toList.last
/**
* Finds the index of the last occurrence of some value in this NonEmptyList
.
*
* @param elem the element value to search for.
* @return the index of the last element of this NonEmptyList
that is equal (as determined by ==
) to elem
,
* or -1
, if none exists.
*/
final def lastIndexOf[U >: T](elem: U): Int = toList.lastIndexOf(elem)
/**
* Finds the index of the last occurrence of some value in this NonEmptyList
before or at a given end
index.
*
* @param elem the element value to search for.
* @param end the end index.
* @return the index >=
end
of the last element of this NonEmptyList
that is equal (as determined by ==
)
* to elem
, or -1
, if none exists.
*/
final def lastIndexOf[U >: T](elem: U, end: Int): Int = toList.lastIndexOf(elem, end)
/**
* Finds the last index where this NonEmptyList
contains a given GenSeq
as a slice.
*
* @param that the GenSeq
defining the slice to look for
* @return the last index at which the elements of this NonEmptyList
starting at that index match the elements of
* GenSeq
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: GenSeq[U]): Int = toList.lastIndexOfSlice(that)
/**
* Finds the last index before or at a given end index where this NonEmptyList
contains a given GenSeq
as a slice.
*
* @param that the GenSeq
defining the slice to look for
* @param end the end index
* @return the last index >=
end
at which the elements of this NonEmptyList
starting at that index match the elements of
* GenSeq
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: GenSeq[U], end: Int): Int = toList.lastIndexOfSlice(that, end)
/**
* Finds the last index where this NonEmptyList
contains a given Every
as a slice.
*
* @param that the Every
defining the slice to look for
* @return the last index at which the elements of this NonEmptyList
starting at that index match the elements of
* Every
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: Every[U]): Int = toList.lastIndexOfSlice(that.toVector)
/**
* Finds the last index where this NonEmptyList
contains a given NonEmptyList
as a slice.
*
* @param that the NonEmptyList
defining the slice to look for
* @return the last index at which the elements of this NonEmptyList
starting at that index match the elements of
* NonEmptyList
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: NonEmptyList[U]): Int = toList.lastIndexOfSlice(that.toList)
/**
* Finds the last index before or at a given end index where this NonEmptyList
contains a given Every
as a slice.
*
* @param that the Every
defining the slice to look for
* @param end the end index
* @return the last index >=
end
at which the elements of this NonEmptyList
starting at that index match the elements of
* Every
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: Every[U], end: Int): Int = toList.lastIndexOfSlice(that.toVector, end)
/**
* Finds the last index before or at a given end index where this NonEmptyList
contains a given NonEmptyList
as a slice.
*
* @param that the NonEmptyList
defining the slice to look for
* @param end the end index
* @return the last index >=
end
at which the elements of this NonEmptyList
starting at that index match the elements of
* NonEmptyList
that
, or -1
of no such subsequence exists.
*/
final def lastIndexOfSlice[U >: T](that: NonEmptyList[U], end: Int): Int = toList.lastIndexOfSlice(that.toList, end)
/**
* Finds index of last element satisfying some predicate.
*
* @param p the predicate used to test elements.
* @return the index of the last element of this NonEmptyList
that satisfies the predicate p
, or -1
, if none exists.
*/
final def lastIndexWhere(p: T => Boolean): Int = toList.lastIndexWhere(p)
/**
* Finds index of last element satisfying some predicate before or at given end index.
*
* @param p the predicate used to test elements.
* @param end the end index
* @return the index >=
end
of the last element of this NonEmptyList
that satisfies the predicate p
,
* or -1
, if none exists.
*/
final def lastIndexWhere(p: T => Boolean, end: Int): Int = toList.lastIndexWhere(p, end)
/**
* Returns the last element of this NonEmptyList
, wrapped in a Some
.
*
* @return the last element, wrapped in a Some
.
*/
final def lastOption: Option[T] = toList.lastOption // Will always return a Some
/**
* The length of this NonEmptyList
.
*
*
* Note: length
and size
yield the same result, which will be >
= 1.
*
*
* @return the number of elements in this NonEmptyList
.
*/
final def length: Int = toList.length
/**
* Compares the length of this NonEmptyList
to a test value.
*
* @param len the test value that gets compared with the length.
* @return a value x
where
*
*
* x < 0 if this.length < len
* x == 0 if this.length == len
* x > 0 if this.length > len
*
*/
final def lengthCompare(len: Int): Int = toList.lengthCompare(len)
/**
* Builds a new NonEmptyList
by applying a function to all elements of this NonEmptyList
.
*
* @tparam U the element type of the returned NonEmptyList
.
* @param f the function to apply to each element.
* @return a new NonEmptyList
resulting from applying the given function f
to each element of this NonEmptyList
and collecting the results.
*/
final def map[U](f: T => U): NonEmptyList[U] =
new NonEmptyList(toList.map(f))
/**
* Finds the largest element.
*
* @return the largest element of this NonEmptyList
.
*/
final def max[U >: T](implicit cmp: Ordering[U]): T = toList.max(cmp)
/**
* Finds the largest result after applying the given function to every element.
*
* @return the largest result of applying the given function to every element of this NonEmptyList
.
*/
final def maxBy[U](f: T => U)(implicit cmp: Ordering[U]): T = toList.maxBy(f)(cmp)
/**
* Finds the smallest element.
*
* @return the smallest element of this NonEmptyList
.
*/
final def min[U >: T](implicit cmp: Ordering[U]): T = toList.min(cmp)
/**
* Finds the smallest result after applying the given function to every element.
*
* @return the smallest result of applying the given function to every element of this NonEmptyList
.
*/
final def minBy[U](f: T => U)(implicit cmp: Ordering[U]): T = toList.minBy(f)(cmp)
/**
* Displays all elements of this NonEmptyList
in a string.
*
* @return a string representation of this NonEmptyList
. In the resulting string, the result of invoking toString
on all elements of this
* NonEmptyList
follow each other without any separator string.
*/
final def mkString: String = toList.mkString
/**
* Displays all elements of this NonEmptyList
in a string using a separator string.
*
* @param sep the separator string
* @return a string representation of this NonEmptyList
. In the resulting string, the result of invoking toString
on all elements of this
* NonEmptyList
are separated by the string sep
.
*/
final def mkString(sep: String): String = toList.mkString(sep)
/**
* Displays all elements of this NonEmptyList
in a string using start, end, and separator strings.
*
* @param start the starting string.
* @param sep the separator string.
* @param end the ending string.
* @return a string representation of this NonEmptyList
. The resulting string begins with the string start
and ends with the string
* end
. Inside, In the resulting string, the result of invoking toString
on all elements of this NonEmptyList
are
* separated by the string sep
.
*/
final def mkString(start: String, sep: String, end: String): String = toList.mkString(start, sep, end)
/**
* Returns true
to indicate this NonEmptyList
, like all NonEmptyList
s, is non-empty.
*
* @return true
*/
final def nonEmpty: Boolean = true
/**
* A copy of this NonEmptyList
with an element value appended until a given target length is reached.
*
* @param len the target length
* @param elem he padding value
* @return a new NonEmptyList
consisting of all elements of this NonEmptyList
followed by the minimal number of occurrences
* of elem
so that the resulting NonEmptyList
has a length of at least len
.
*/
final def padTo[U >: T](len: Int, elem: U): NonEmptyList[U] =
new NonEmptyList(toList.padTo(len, elem))
/**
* Produces a new NonEmptyList
where a slice of elements in this NonEmptyList
is replaced by another NonEmptyList
*
* @param from the index of the first replaced element
* @param that the NonEmptyList
whose elements should replace a slice in this NonEmptyList
* @param replaced the number of elements to drop in the original NonEmptyList
*/
final def patch[U >: T](from: Int, that: NonEmptyList[U], replaced: Int): NonEmptyList[U] =
new NonEmptyList(toList.patch(from, that.toVector, replaced))
/**
* Iterates over distinct permutations.
*
*
* Here's an example:
*
*
*
* NonEmptyList('a', 'b', 'b').permutations.toList = List(NonEmptyList(a, b, b), NonEmptyList(b, a, b), NonEmptyList(b, b, a))
*
*
* @return an iterator that traverses the distinct permutations of this NonEmptyList
.
*/
final def permutations: Iterator[NonEmptyList[T]] = {
val it = toList.permutations
it map { list => new NonEmptyList(list) }
}
/**
* Returns the length of the longest prefix whose elements all satisfy some predicate.
*
* @param p the predicate used to test elements.
* @return the length of the longest prefix of this NonEmptyList
such that every element
* of the segment satisfies the predicate p
.
*/
final def prefixLength(p: T => Boolean): Int = toList.prefixLength(p)
/**
* The result of multiplying all the elements of this NonEmptyList
.
*
*
* This method can be invoked for any NonEmptyList[T]
for which an implicit Numeric[T]
exists.
*
*
* @return the product of all elements
*/
final def product[U >: T](implicit num: Numeric[U]): U = toList.product(num)
/**
* Reduces the elements of this NonEmptyList
using the specified associative binary operator.
*
*
* The order in which operations are performed on elements is unspecified and may be nondeterministic.
*
*
* @tparam U a type parameter for the binary operator, a supertype of T.
* @param op a binary operator that must be associative.
* @return the result of applying reduce operator op
between all the elements of this NonEmptyList
.
*/
final def reduce[U >: T](op: (U, U) => U): U = toList.reduce(op)
/**
* Applies a binary operator to all elements of this NonEmptyList
, going left to right.
*
* @tparam U the result type of the binary operator.
* @param op the binary operator.
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going left to right:
*
*
* op(...op(op(x_1, x_2), x_3), ..., x_n)
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
final def reduceLeft[U >: T](op: (U, T) => U): U = toList.reduceLeft(op)
/**
* Applies a binary operator to all elements of this NonEmptyList
, going left to right, returning the result in a Some
.
*
* @tparam U the result type of the binary operator.
* @param op the binary operator.
* @return a Some
containing the result of reduceLeft(op)
*
*/
final def reduceLeftOption[U >: T](op: (U, T) => U): Option[U] = toList.reduceLeftOption(op)
final def reduceOption[U >: T](op: (U, U) => U): Option[U] = toList.reduceOption(op)
/**
* Applies a binary operator to all elements of this NonEmptyList
, going right to left.
*
* @tparam U the result of the binary operator
* @param op the binary operator
* @return the result of inserting op
between consecutive elements of this NonEmptyList
, going right to left:
*
*
* op(x_1, op(x_2, ... op(x_{n-1}, x_n)...))
*
*
*
* where x1, ..., xn are the elements of this NonEmptyList
.
*
*/
final def reduceRight[U >: T](op: (T, U) => U): U = toList.reduceRight(op)
/**
* Applies a binary operator to all elements of this NonEmptyList
, going right to left, returning the result in a Some
.
*
* @tparam U the result of the binary operator
* @param op the binary operator
* @return a Some
containing the result of reduceRight(op)
*/
final def reduceRightOption[U >: T](op: (T, U) => U): Option[U] = toList.reduceRightOption(op)
/**
* Returns new NonEmptyList
with elements in reverse order.
*
* @return a new NonEmptyList
with all elements of this NonEmptyList
in reversed order.
*/
final def reverse: NonEmptyList[T] =
new NonEmptyList(toList.reverse)
/**
* An iterator yielding elements in reverse order.
*
*
* Note: nonEmptyList.reverseIterator
is the same as nonEmptyList.reverse.iterator
, but might be more efficient.
*
*
* @return an iterator yielding the elements of this NonEmptyList
in reversed order
*/
final def reverseIterator: Iterator[T] = toList.reverseIterator
/**
* Builds a new NonEmptyList
by applying a function to all elements of this NonEmptyList
and collecting the results in reverse order.
*
*
* Note: nonEmptyList.reverseMap(f)
is the same as nonEmptyList.reverse.map(f)
, but might be more efficient.
*
*
* @tparam U the element type of the returned NonEmptyList
.
* @param f the function to apply to each element.
* @return a new NonEmptyList
resulting from applying the given function f
to each element of this NonEmptyList
* and collecting the results in reverse order.
*/
final def reverseMap[U](f: T => U): NonEmptyList[U] =
new NonEmptyList(toList.reverseMap(f))
/**
* Checks if the given GenIterable
contains the same elements in the same order as this NonEmptyList
.
*
* @param that the GenIterable
with which to compare
* @return true
, if both this NonEmptyList
and the given GenIterable
contain the same elements
* in the same order, false
otherwise.
*/
final def sameElements[U >: T](that: GenIterable[U]): Boolean = toList.sameElements(that)
/**
* Checks if the given Every
contains the same elements in the same order as this NonEmptyList
.
*
* @param that the Every
with which to compare
* @return true
, if both this and the given Every
contain the same elements
* in the same order, false
otherwise.
*/
final def sameElements[U >: T](that: Every[U]): Boolean = toList.sameElements(that.toVector)
/**
* Checks if the given NonEmptyList
contains the same elements in the same order as this NonEmptyList
.
*
* @param that the NonEmptyList
with which to compare
* @return true
, if both this and the given NonEmptyList
contain the same elements
* in the same order, false
otherwise.
*/
final def sameElements[U >: T](that: NonEmptyList[U]): Boolean = toList.sameElements(that.toList)
/**
* Computes a prefix scan of the elements of this NonEmptyList
.
*
*
* Note: The neutral element z may be applied more than once.
*
*
*
* Here are some examples:
*
*
*
* NonEmptyList(1, 2, 3).scan(0)(_ + _) == NonEmptyList(0, 1, 3, 6)
* NonEmptyList(1, 2, 3).scan("z")(_ + _.toString) == NonEmptyList("z", "z1", "z12", "z123")
*
*
* @tparam U a type parameter for the binary operator, a supertype of T, and the type of the resulting NonEmptyList
.
* @param z a neutral element for the scan operation; may be added to the result an arbitrary number of
* times, and must not change the result (e.g., Nil
for list concatenation,
* 0 for addition, or 1 for multiplication.)
* @param op a binary operator that must be associative
* @return a new NonEmptyList
containing the prefix scan of the elements in this NonEmptyList
*/
final def scan[U >: T](z: U)(op: (U, U) => U): NonEmptyList[U] = new NonEmptyList(toList.scan(z)(op))
/**
* Produces a NonEmptyList
containing cumulative results of applying the operator going left to right.
*
*
* Here are some examples:
*
*
*
* NonEmptyList(1, 2, 3).scanLeft(0)(_ + _) == NonEmptyList(0, 1, 3, 6)
* NonEmptyList(1, 2, 3).scanLeft("z")(_ + _) == NonEmptyList("z", "z1", "z12", "z123")
*
*
* @tparam B the result type of the binary operator and type of the resulting NonEmptyList
* @param z the start value.
* @param op the binary operator.
* @return a new NonEmptyList
containing the intermediate results of inserting op
between consecutive elements of this NonEmptyList
,
* going left to right, with the start value, z
, on the left.
*/
final def scanLeft[B](z: B)(op: (B, T) => B): NonEmptyList[B] = new NonEmptyList(toList.scanLeft(z)(op))
/**
* Produces a NonEmptyList
containing cumulative results of applying the operator going right to left.
*
*
* Here are some examples:
*
*
*
* NonEmptyList(1, 2, 3).scanRight(0)(_ + _) == NonEmptyList(6, 5, 3, 0)
* NonEmptyList(1, 2, 3).scanRight("z")(_ + _) == NonEmptyList("123z", "23z", "3z", "z")
*
*
* @tparam B the result of the binary operator and type of the resulting NonEmptyList
* @param z the start value
* @param op the binary operator
* @return a new NonEmptyList
containing the intermediate results of inserting op
between consecutive elements of this NonEmptyList
,
* going right to left, with the start value, z
, on the right.
*/
final def scanRight[B](z: B)(op: (T, B) => B): NonEmptyList[B] = new NonEmptyList(toList.scanRight(z)(op))
/**
* Computes length of longest segment whose elements all satisfy some predicate.
*
* @param p the predicate used to test elements.
* @param from the index where the search starts.
* @param the length of the longest segment of this NonEmptyList
starting from index from
such that every element of the
* segment satisfies the predicate p
.
*/
final def segmentLength(p: T => Boolean, from: Int): Int = toList.segmentLength(p, from)
/**
* Groups elements in fixed size blocks by passing a “sliding window” over them (as opposed to partitioning them, as is done in grouped.)
*
* @param size the number of elements per group
* @return an iterator producing NonEmptyList
s of size size
, except the last and the only element will be truncated
* if there are fewer elements than size
.
*/
final def sliding(size: Int): Iterator[NonEmptyList[T]] = toList.sliding(size).map(new NonEmptyList(_))
/**
* Groups elements in fixed size blocks by passing a “sliding window” over them (as opposed to partitioning them, as is done in grouped.),
* moving the sliding window by a given step
each time.
*
* @param size the number of elements per group
* @param step the distance between the first elements of successive groups
* @return an iterator producing NonEmptyList
s of size size
, except the last and the only element will be truncated
* if there are fewer elements than size
.
*/
final def sliding(size: Int, step: Int): Iterator[NonEmptyList[T]] = toList.sliding(size, step).map(new NonEmptyList(_))
/**
* The size of this NonEmptyList
.
*
*
* Note: length
and size
yield the same result, which will be >
= 1.
*
*
* @return the number of elements in this NonEmptyList
.
*/
final def size: Int = toList.size
/**
* Sorts this NonEmptyList
according to the Ordering
of the result of applying the given function to every element.
*
* @tparam U the target type of the transformation f
, and the type where the Ordering
ord
is defined.
* @param f the transformation function mapping elements to some other domain U
.
* @param ord the ordering assumed on domain U
.
* @return a NonEmptyList
consisting of the elements of this NonEmptyList
sorted according to the Ordering
where
* x < y if ord.lt(f(x), f(y))
.
*/
final def sortBy[U](f: T => U)(implicit ord: Ordering[U]): NonEmptyList[T] = new NonEmptyList(toList.sortBy(f))
/**
* Sorts this NonEmptyList
according to a comparison function.
*
*
* The sort is stable. That is, elements that are equal (as determined by lt
) appear in the same order in the
* sorted NonEmptyList
as in the original.
*
*
* @param the comparison function that tests whether its first argument precedes its second argument in the desired ordering.
* @return a NonEmptyList
consisting of the elements of this NonEmptyList
sorted according to the comparison function lt
.
*/
final def sortWith(lt: (T, T) => Boolean): NonEmptyList[T] = new NonEmptyList(toList.sortWith(lt))
/**
* Sorts this NonEmptyList
according to an Ordering
.
*
*
* The sort is stable. That is, elements that are equal (as determined by lt
) appear in the same order in the
* sorted NonEmptyList
as in the original.
*
*
* @param ord the Ordering
to be used to compare elements.
* @param the comparison function that tests whether its first argument precedes its second argument in the desired ordering.
* @return a NonEmptyList
consisting of the elements of this NonEmptyList
sorted according to the comparison function lt
.
*/
final def sorted[U >: T](implicit ord: Ordering[U]): NonEmptyList[U] = new NonEmptyList(toList.sorted(ord))
/**
* Indicates whether this NonEmptyList
starts with the given GenSeq
.
*
* @param that the GenSeq
slice to look for in this NonEmptyList
* @return true
if this NonEmptyList
has that
as a prefix, false
otherwise.
*/
final def startsWith[B](that: GenSeq[B]): Boolean = toList.startsWith(that)
/**
* Indicates whether this NonEmptyList
starts with the given GenSeq
at the given index.
*
* @param that the GenSeq
slice to look for in this NonEmptyList
* @param offset the index at which this NonEmptyList
is searched.
* @return true
if this NonEmptyList
has that
as a slice at the index offset
, false
otherwise.
*/
final def startsWith[B](that: GenSeq[B], offset: Int): Boolean = toList.startsWith(that, offset)
/**
* Indicates whether this NonEmptyList
starts with the given Every
.
*
* @param that the Every
to test
* @return true
if this collection has that
as a prefix, false
otherwise.
*/
final def startsWith[B](that: Every[B]): Boolean = toList.startsWith(that.toVector)
/**
* Indicates whether this NonEmptyList
starts with the given NonEmptyList
.
*
* @param that the NonEmptyList
to test
* @return true
if this collection has that
as a prefix, false
otherwise.
*/
final def startsWith[B](that: NonEmptyList[B]): Boolean = toList.startsWith(that.toList)
/**
* Indicates whether this NonEmptyList
starts with the given Every
at the given index.
*
* @param that the Every
slice to look for in this NonEmptyList
* @param offset the index at which this NonEmptyList
is searched.
* @return true
if this NonEmptyList
has that
as a slice at the index offset
, false
otherwise.
*/
final def startsWith[B](that: Every[B], offset: Int): Boolean = toList.startsWith(that.toVector, offset)
/**
* Indicates whether this NonEmptyList
starts with the given NonEmptyList
at the given index.
*
* @param that the NonEmptyList
slice to look for in this NonEmptyList
* @param offset the index at which this NonEmptyList
is searched.
* @return true
if this NonEmptyList
has that
as a slice at the index offset
, false
otherwise.
*/
final def startsWith[B](that: NonEmptyList[B], offset: Int): Boolean = toList.startsWith(that.toList, offset)
/**
* Returns "NonEmptyList"
, the prefix of this object's toString
representation.
*
* @return the string "NonEmptyList"
*/
def stringPrefix: String = "NonEmptyList"
/**
* The result of summing all the elements of this NonEmptyList
.
*
*
* This method can be invoked for any NonEmptyList[T]
for which an implicit Numeric[T]
exists.
*
*
* @return the sum of all elements
*/
final def sum[U >: T](implicit num: Numeric[U]): U = toList.sum(num)
import scala.language.higherKinds
//import scala.collection.compat._
/**
* Converts this NonEmptyList
into a collection of type Col
by copying all elements.
*
* @tparam Col the collection type to build.
* @return a new collection containing all elements of this NonEmptyList
.
*/
/*final def to[Col[_]](implicit cbf: org.scalactic.ColCompatHelper.BuildFrom[Nothing, T, Col[T @ uV]]): Col[T @ uV] = {
toList.to(Col[T])
}*/
final def to[Col[_]](factory: org.scalactic.ColCompatHelper.Factory[T, Col[T @ uV]]): Col[T @ uV] = /*{
toList.to(
new scala.collection.generic.CanBuildFrom[Nothing, T, Col[T @ uV]] {
def apply(): scala.collection.mutable.Builder[T, Col[T @ uV]] = factory.newBuilder
def apply(from: Nothing): scala.collection.mutable.Builder[T, Col[T @ uV]] = factory.newBuilder
}
)
}*/
//toList.to(factory)
//org.scalactic.ColCompatHelper.toImpl(toList, factory)
toList.to(factory)
/**
* Converts this NonEmptyList
to an array.
*
* @return an array containing all elements of this NonEmptyList
. A ClassTag
must be available for the element type of this NonEmptyList
.
*/
final def toArray[U >: T](implicit classTag: ClassTag[U]): Array[U] = toList.toArray
/**
* Converts this NonEmptyList
to a Vector
.
*
* @return a Vector
containing all elements of this NonEmptyList
.
*/
final def toVector: Vector[T] = toList.toVector
/**
* Converts this NonEmptyList
to a mutable buffer.
*
* @return a buffer containing all elements of this NonEmptyList
.
*/
final def toBuffer[U >: T]: Buffer[U] = toList.toBuffer
/**
* Converts this NonEmptyList
to an immutable IndexedSeq
.
*
* @return an immutable IndexedSeq
containing all elements of this NonEmptyList
.
*/
final def toIndexedSeq: collection.immutable.IndexedSeq[T] = toList.toVector
/**
* Converts this NonEmptyList
to an iterable collection.
*
* @return an Iterable
containing all elements of this NonEmptyList
.
*/
final def toIterable: Iterable[T] = toList.toIterable
/**
* Returns an Iterator
over the elements in this NonEmptyList
.
*
* @return an Iterator
containing all elements of this NonEmptyList
.
*/
final def toIterator: Iterator[T] = toList.toIterator
/**
* Converts this NonEmptyList
to a list.
*
* @return a list containing all elements of this NonEmptyList
.
*/
// final def toList: List[T] = toList
/**
* Converts this NonEmptyList
to a map.
*
*
* This method is unavailable unless the elements are members of Tuple2
, each ((K, V))
becoming a key-value pair
* in the map. Duplicate keys will be overwritten by later keys.
*
*
* @return a map of type immutable.Map[K, V]
containing all key/value pairs of type (K, V)
of this NonEmptyList
.
*/
final def toMap[K, V](implicit ev: T <:< (K, V)): Map[K, V] = toList.toMap
/**
* Converts this NonEmptyList
to an immutable IndexedSeq
.
*
* @return an immutable IndexedSeq
containing all elements of this NonEmptyList
.
*/
final def toSeq: collection.immutable.Seq[T] = toList
/**
* Converts this NonEmptyList
to a set.
*
* @return a set containing all elements of this NonEmptyList
.
*/
final def toSet[U >: T]: Set[U] = toList.toSet
/**
* Converts this NonEmptyList
to a stream.
*
* @return a stream containing all elements of this NonEmptyList
.
*/
final def toStream: Stream[T] = toList.toStream
/**
* Returns a string representation of this NonEmptyList
.
*
* @return the string "NonEmptyList"
followed by the result of invoking toString
on
* this NonEmptyList
's elements, surrounded by parentheses.
*/
override def toString: String = "NonEmptyList(" + toList.mkString(", ") + ")"
final def transpose[U](implicit ev: T <:< NonEmptyList[U]): NonEmptyList[NonEmptyList[U]] = {
val asLists = toList.map(ev)
val list = asLists.transpose
new NonEmptyList(list.map(new NonEmptyList(_)))
}
/**
* Produces a new NonEmptyList
that contains all elements of this NonEmptyList
and also all elements of a given Every
.
*
*
* nonEmptyListX
union
everyY
is equivalent to nonEmptyListX
++
everyY
.
*
*
*
* Another way to express this is that nonEmptyListX
union
everyY
computes the order-presevring multi-set union
* of nonEmptyListX
and everyY
. This union
method is hence a counter-part of diff
and intersect
that
* also work on multi-sets.
*
*
* @param that the Every
to add.
* @return a new NonEmptyList
that contains all elements of this NonEmptyList
followed by all elements of that
Every
.
*/
final def union[U >: T](that: Every[U]): NonEmptyList[U] = new NonEmptyList(toList union that.toVector)
/**
* Produces a new NonEmptyList
that contains all elements of this NonEmptyList
and also all elements of a given NonEmptyList
.
*
*
* nonEmptyListX
union
nonEmptyListY
is equivalent to nonEmptyListX
++
nonEmptyListY
.
*
*
*
* Another way to express this is that nonEmptyListX
union
nonEmptyListY
computes the order-presevring multi-set union
* of nonEmptyListX
and nonEmptyListY
. This union
method is hence a counter-part of diff
and intersect
that
* also work on multi-sets.
*
*
* @param that the NonEmptyList
to add.
* @return a new NonEmptyList
that contains all elements of this NonEmptyList
followed by all elements of that
.
*/
final def union[U >: T](that: NonEmptyList[U]): NonEmptyList[U] = new NonEmptyList(toList union that.toList)
/**
* Produces a new NonEmptyList
that contains all elements of this NonEmptyList
and also all elements of a given GenSeq
.
*
*
* nonEmptyListX
union
ys
is equivalent to nonEmptyListX
++
ys
.
*
*
*
* Another way to express this is that nonEmptyListX
union
ys
computes the order-presevring multi-set union
* of nonEmptyListX
and ys
. This union
method is hence a counter-part of diff
and intersect
that
* also work on multi-sets.
*
*
* @param that the GenSeq
to add.
* @return a new NonEmptyList
that contains all elements of this NonEmptyList
followed by all elements of that
GenSeq
.
*/
final def union[U >: T](that: GenSeq[U]): NonEmptyList[U] = new NonEmptyList(toList.union(that))
/**
* Converts this NonEmptyList
of pairs into two NonEmptyList
s of the first and second half of each pair.
*
* @tparam L the type of the first half of the element pairs
* @tparam R the type of the second half of the element pairs
* @param asPair an implicit conversion that asserts that the element type of this NonEmptyList
is a pair.
* @return a pair of NonEmptyList
s, containing the first and second half, respectively, of each element pair of this NonEmptyList
.
*/
final def unzip[L, R](implicit asPair: T => (L, R)): (NonEmptyList[L], NonEmptyList[R]) = {
val unzipped = toList.unzip
(new NonEmptyList(unzipped._1), new NonEmptyList(unzipped._2))
}
/**
* Converts this NonEmptyList
of triples into three NonEmptyList
s of the first, second, and and third element of each triple.
*
* @tparam L the type of the first member of the element triples
* @tparam R the type of the second member of the element triples
* @tparam R the type of the third member of the element triples
* @param asTriple an implicit conversion that asserts that the element type of this NonEmptyList
is a triple.
* @return a triple of NonEmptyList
s, containing the first, second, and third member, respectively, of each element triple of this NonEmptyList
.
*/
final def unzip3[L, M, R](implicit asTriple: T => (L, M, R)): (NonEmptyList[L], NonEmptyList[M], NonEmptyList[R]) = {
val unzipped = toList.unzip3
(new NonEmptyList(unzipped._1), new NonEmptyList(unzipped._2), new NonEmptyList(unzipped._3))
}
/**
* A copy of this NonEmptyList
with one single replaced element.
*
* @param idx the position of the replacement
* @param elem the replacing element
* @throws IndexOutOfBoundsException if the passed index is greater than or equal to the length of this NonEmptyList
* @return a copy of this NonEmptyList
with the element at position idx
replaced by elem
.
*/
final def updated[U >: T](idx: Int, elem: U): NonEmptyList[U] =
try new NonEmptyList(toList.updated(idx, elem))
catch { case _: UnsupportedOperationException => throw new IndexOutOfBoundsException(idx.toString) } // This is needed for 2.10 support. Can drop after.
// Because 2.11 throws IndexOutOfBoundsException.
/**
* Returns a NonEmptyList
formed from this NonEmptyList
and an iterable collection by combining corresponding
* elements in pairs. If one of the two collections is shorter than the other, placeholder elements will be used to extend the
* shorter collection to the length of the longer.
*
* @tparm O the type of the second half of the returned pairs
* @tparm U the type of the first half of the returned pairs
* @param other the Iterable
providing the second half of each result pair
* @param thisElem the element to be used to fill up the result if this NonEmptyList
is shorter than that
Iterable
.
* @param thatElem the element to be used to fill up the result if that
Iterable
is shorter than this NonEmptyList
.
* @return a new NonEmptyList
containing pairs consisting of corresponding elements of this NonEmptyList
and that
. The
* length of the returned collection is the maximum of the lengths of this NonEmptyList
and that
. If this NonEmptyList
* is shorter than that
, thisElem
values are used to pad the result. If that
is shorter than this
* NonEmptyList
, thatElem
values are used to pad the result.
*/
final def zipAll[O, U >: T](other: collection.Iterable[O], thisElem: U, otherElem: O): NonEmptyList[(U, O)] =
new NonEmptyList(toList.zipAll(other, thisElem, otherElem))
/**
* Zips this NonEmptyList
with its indices.
*
* @return A new NonEmptyList
containing pairs consisting of all elements of this NonEmptyList
paired with their index. Indices start at 0.
*/
final def zipWithIndex: NonEmptyList[(T, Int)] = new NonEmptyList(toList.zipWithIndex)
}
/**
* Companion object for class NonEmptyList
.
*/
object NonEmptyList {
/**
* Constructs a new NonEmptyList
given at least one element.
*
* @tparam T the type of the element contained in the new NonEmptyList
* @param firstElement the first element (with index 0) contained in this NonEmptyList
* @param otherElements a varargs of zero or more other elements (with index 1, 2, 3, ...) contained in this NonEmptyList
*/
def apply[T](firstElement: T, otherElements: T*): NonEmptyList[T] = new NonEmptyList(firstElement :: otherElements.toList)
/**
* Variable argument extractor for NonEmptyList
s.
*
* @param nonEmptyList: the NonEmptyList
containing the elements to extract
* @return an Seq
containing this NonEmptyList
s elements, wrapped in a Some
*/
def unapplySeq[T](nonEmptyList: NonEmptyList[T]): Option[Seq[T]] = Some(nonEmptyList.toList)
/*
// TODO: Figure out how to get case NonEmptyList() to not compile
def unapplySeq[T](nonEmptyList: NonEmptyList[T]): Option[(T, Seq[T])] = Some(nonEmptyList.head, nonEmptyList.tail)
*/
/**
* Optionally construct a NonEmptyList
containing the elements, if any, of a given GenSeq
.
*
* @param seq the GenSeq
with which to construct a NonEmptyList
* @return a NonEmptyList
containing the elements of the given GenSeq
, if non-empty, wrapped in
* a Some
; else None
if the GenSeq
is empty
*/
def from[T](seq: GenSeq[T]): Option[NonEmptyList[T]] =
seq.headOption match {
case None => None
case Some(first) => Some(new NonEmptyList(first :: seq.tail.toList))
}
import scala.language.implicitConversions
/**
* Implicit conversion from NonEmptyList
to List
.
*
*
* One use case for this implicit conversion is to enable GenSeq[NonEmptyList]
s to be flattened.
* Here's an example:
*
*
*
* scala> Vector(NonEmptyList(1, 2, 3), NonEmptyList(3, 4), NonEmptyList(5, 6, 7, 8)).flatten
* res0: scala.collection.immutable.Vector[Int] = Vector(1, 2, 3, 3, 4, 5, 6, 7, 8)
*
*
* @param nonEmptyList the NonEmptyList
to convert to a List
* @return a List
containing the elements, in order, of this NonEmptyList
*/
implicit def nonEmptyListToList[E](nonEmptyList: NonEmptyList[E]): scala.collection.immutable.List[E] = nonEmptyList.toList
}