Stata 15 help for while

[P] while -- Looping

Syntax

while exp { stata_commands }

Braces must be specified with while, and

1. the open brace must appear on the same line as while;

2. nothing may follow the open brace, except, of course, comments; the first command to be executed must appear on a new line;

3. the close brace must appear on a line by itself.

Description

while evaluates exp and, if it is true (nonzero), executes the stata_commands enclosed in the braces. It then repeats the process until exp evaluates to false (zero). whiles may be nested within whiles. If the exp refers to any variables, their values in the first observation are used unless explicit subscripts are specified; see [U] 13.7 Explicit subscripting.

Also see [P] foreach and [P] forvalues for alternatives to while.

Example 1

program ... ... gettoken tok 0 : 0 while "`tok'" != "" { ... gettoken tok 0 : 0 } ... end

Example 2

while may be used interactively. Here we use it to generate several uniform random variables.

. set obs 10 . local i = 1 . while `i' < 40 { 2. gen u`i' = runiform() 3. local i = `i' + 1 4. } . list u1 - u7


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