**[R] fvrevar** -- Factor-variables operator programming command

__Syntax__

**fvrevar** [*varlist*] [*if*] [*in*] [**,** __sub__**stitute** __ts__**only** __l__**ist** **stub(***stub***)**]

You must **tsset** your data before using **fvrevar** if *varlist* contains
time-series operators; see **[TS] tsset**.

__Description__

**fvrevar** creates a variable list that includes equivalent, temporary
variables in place of the factor variables, interactions, or
time-series-operated variables in *varlist*. The resulting variable list
can be used by commands that do not otherwise support factor variables or
time-series-operated variables. The resulting list also could be used in
a program to speed execution at the cost of using more memory.

__Options__

**substitute** specifies that equivalent, temporary variables be substituted
for any factor variables, interactions, or time-series-operated
variables in *varlist*. **substitute** is the default action taken by
**fvrevar**; you do not need to specify the option.

**tsonly** specifies that equivalent, temporary variables be substituted for
only the time-series-operated variables in *varlist*.

**list** specifies that all factor-variable operators and time-series
operators be removed from *varlist* and the resulting list of base
variables be returned in **r(varlist)**. No new variables are created
with this option.

**stub(***stub***)** specifies that **fvrevar** generate named variables instead of
temporary variables. The new variables will be named *stub#*.

__Examples__

Setup
**. sysuse auto**

Describe the data
**. describe**

Create five temporary variables containing the values for each level of
factor variable **rep78**
**. fvrevar i.rep78**

Show contents of **r(varlist)**
**. display "`r(varlist)'"**

Do not create temporary variables and only return the list corresponding
to the unoperated base variable of **i.rep78**
**. fvrevar i.rep78, list**

Show contents of **r(varlist)**
**. display "`r(varlist)'"**

Only create two temporary variables corresponding to levels **2** and **3** of
factor variable **rep78**
**. fvrevar i(2,3).rep78**

Show contents of **r(varlist)**
**. display "`r(varlist)'"**

__Stored results__

**fvrevar** stores the following in **r()**:

Macros
**r(varlist)** the modified variable list or list of base-variable
names