Recode Variables

Description

The Recode Variables Dialog allows you to create new variables based on the values of current variables.

This manual page uses the mtcars data set, which can be loaded by entering data(mtcars) into the console.

Selecting variables

To select a variable to recode, simply drag the variable from the variable selection list on the left to the 'variables to recode' list on the right. By default, the recoded variable overwrites the old variable. The 'Target' button allows the saving of the recoded variable to a new variable in the data frame.

In mtcars the cyl variable indicates how many cylinders a car has. We will recode this into a new variable V8 that will be 1 if the number of cylinders is 8 and 0 otherwise. First we drag cyl to the list on the right, and then click target to specify V8 as the target variable name.

Clicking the 'Define Recode' button allows us to specify how the recoding should be done.

Defining codes

The panel on the left shows variable information that might be useful to know while doing the recoding. For numeric variables a table of percentiles is shown. For factor and character variables, a table of frequencies is displayed. The 'code' panel allows the specification of the recoding. Note that a value can be recoded to missing by entering NA into the appropriate field.

Here we wish to recode 8 into 1, and all other values into 0.

R Code

This dialog uses the recode.variables function. The example produces the following call:

mtcars[c("V8")] <- recode.variables(mtcars[c("cyl")] , "8 -> 1;else -> 0;")