### 11.7 MODIFY VARS

    MODIFY VARS
            /REORDER={FORWARD,BACKWARD} {POSITIONAL,ALPHA} (var_list)…
            /RENAME=(old_names=new_names)…
            /{DROP,KEEP}=var_list
            /MAP

`MODIFY VARS` reorders, renames, and deletes variables in the active dataset.

At least one subcommand must be specified, and no subcommand may be specified more than once. `DROP` and `KEEP` may not both be specified.

The `REORDER` subcommand changes the order of variables in the active dataset. Specify one or more lists of variable names in parentheses. By default, each list of variables is rearranged into the specified order. To put the variables into the reverse of the specified order, put keyword `BACKWARD` before the parentheses. To put them into alphabetical order in the dictionary, specify keyword `ALPHA` before the parentheses. `BACKWARD` and `ALPHA` may also be combined.

To rename variables in the active dataset, specify `RENAME`, an equals sign (‘`=`’), and lists of the old variable names and new variable names separated by another equals sign within parentheses. There must be the same number of old and new variable names. Each old variable is renamed to the corresponding new variable name. Multiple parenthesized groups of variables may be specified.

The `DROP` subcommand deletes a specified list of variables from the active dataset.

The `KEEP` subcommand keeps the specified list of variables in the active dataset. Any unlisted variables are deleted from the active dataset.

`MAP` is currently ignored.

If either `DROP` or `KEEP` is specified, the data is read; otherwise it is not.

`MODIFY VARS` may not be specified following `TEMPORARY` (see TEMPORARY).