Table of contents
TOC
Collapse the table of content
Expand the table of content

About While

JuanPablo Jofre|Last Updated: 11/17/2016
|
2 Contributors

about_While

SHORT DESCRIPTION

Describes a language statement that you can use to run a command block based on the results of a conditional test.

LONG DESCRIPTION

The While statement (also known as a While loop) is a language construct for creating a loop that runs commands in a command block as long as a conditional test evaluates to true. The While statement is easier to construct than a For statement because its syntax is less complicated. In addition, it is more flexible than the Foreach statement because you specify a conditional test in the While statement to control how many times the loop runs.

The following shows the While statement syntax:

while (<condition>){<statement list>}

When you run a While statement, Windows PowerShell� evaluates the section of the statement before entering the section. The condition portion of the statement resolves to either true or false. As long as the condition remains true, Windows PowerShell reruns the section.

The section of the statement contains one or more commands that are run each time the loop is entered or repeated.

For example, the following While statement displays the numbers 1 through 3 if the $val variable has not been created or if the $val variable has been created and initialized to 0.

while($val -ne 3)  
{  
    $val++  
    Write-Host $val  
}

In this example, the condition ($val is not equal to 3) is true while $val = 0, 1, 2. Each time through the loop, $val is incremented by 1 using the ++ unary increment operator ($val++). The last time through the loop, $val = 3. When $val equals 3, the condition statement evaluates to false, and the loop exits.

To conveniently write this command at the Windows PowerShell command prompt, you can enter it in the following way:

while($val -ne 3){$val++; Write-Host $val}

Notice that the semicolon separates the first command that adds 1 to $val from the second command that writes the value of $val to the console.

SEE ALSO

about_Comparison_Operators

about_Do

about_Foreach

about_For

about_Language_Keywords

© 2016 Microsoft