docs.javahelp.manual.common_tasks.manipulating_data.html Maven / Gradle / Ivy
Graph
Loading Data
You can import any tab delimited data . The data file needs a one line header:
For data for continuous variables, which must be numeric the header line is:
/continuous
For data for discrete variables, which can be alphanumeric, the header line is:
/discrete
For a lower triangular covariance or correlation matrix, the header is:
/covariance
You must also include a row with the names of the variables in the appropriate order for the data file or covariance
matrix.
For example, if you write a EXCEL file:with the names of variables in the first row, and save it as a text file, for
example:
/continuous
X1 X2 X3
4 2 1
2 5 0.09
and in the File menu above the Tetrad data sheet click ":Load." Any previous data is erased and you see:
Note that the variable names occur in the correct place at the top of each column. It is essential that the first row of the data file you wish to import
contain the variable names, tab delimited. Also, do not include empty spaces between rows.
A data file does not require that any other boxes have flowgraph edges directed into it. A standalone
Data box can be used to import an external data file.
A data file can be saved by opening the "File" tab and clicking "Save." It can be reloaded just as can any
imported file.
Inside a Tetrad data sheet you can use the mouse to select individual cells, rows or columns. (To select
more than one column or row, hold down the shift key). Then, by opening the Edit tab, you can copy, delete
or insert cells, rows and columns. For example, you can select the X2 column in the picture above, copy it,
select a new empty column, and paste a copy of the selected column in the new column.
The Manip tab in the Tetrad data sheet permits simple manipulations of the data. Other data manipulations
use the Manipulate Data box.
1. Continuous data can be projected to a set of discrete values. For example if you select all of the
colunms in a data sheet