The compute dialog is used to compute new variables.
The name of the new variable must be a valid R object name (consisting only of upper and lower-case letters, numerals, and periods, and not starting with a numeral).
Enter an R expression in the box at the right. The expression is evaluated using the active data set. You can double-click in the variable-list box to enter variable names in the expression. The expression must evaluate to a valid variable, which is added to the active data set.