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about_While

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 <condition> section of the statement before entering the  
    <statement list> section. The condition portion of the statement resolves 
    to either true or false. As long as the condition remains true, Windows  
    PowerShell reruns the <statement list> section. 
 
 
    The <statement list> 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