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package com.webapp.utils.collections;

import java.util.List;
import java.util.stream.Collectors;

public final class ListUtils {

	/**
	 * 求集合的平均值
	 * @param list
	 * @return double
	 */
	public static Double average(List list){
		return list.stream().map(x->x.doubleValue()).collect(Collectors.averagingDouble(d->d));
	}

	/**
	 * 求集合的加和
	 * @param list
	 * @return number
	 */
	public static  Number sum(List list){
//		return list.stream().map(x->x.doubleValue()).collect(Collectors.summingDouble(i->i));
		return list.stream().map(x->x.doubleValue()).reduce(0d, Double::sum);
	}

	/**
	 * 集合去除重复
	 * @param list
	 * @return double
	 */
	public static  List unique(List list) {
		return list.stream().distinct().collect(Collectors.toList());
    }

}