{"id":2003,"date":"2014-02-15T00:01:00","date_gmt":"2014-02-15T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2014\/02\/15\/string-formatting-in-windows-powershell\/"},"modified":"2014-02-15T00:01:00","modified_gmt":"2014-02-15T00:01:00","slug":"string-formatting-in-windows-powershell","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/string-formatting-in-windows-powershell\/","title":{"rendered":"String Formatting in Windows PowerShell"},"content":{"rendered":"

Summary<\/b>: Learn about using formatted strings in Windows PowerShell.\nMicrosoft Scripting Guy, Ed Wilson, here. Today we have another guest blog by June Blender. To read more of June’s previous posts, see these Hey, Scripting Guy Blog posts<\/a>. Now, here’s June…\nI recently had the opportunity to help the Windows Azure and ASP.NET product teams with some Windows PowerShell automation. Although I was supposed to be the helper, I probably learned more from the interaction than anyone else. I learned about Windows Azure and the Azure module for Windows PowerShell. And I learned a whole bunch about Windows PowerShell. I’m convinced that helping always benefits the helper. You always learn by interacting. This case was no exception.\nOne of the most fun things I learned was about string formatting.\nWhen I saw the first drafts of the scripts, they had a lot of Write-Verbose<\/b> calls like this one:<\/p>\n

$VerbosePreference = “Continue”<\/p>\n

$filepath = “C:ps-testtest.txt”<\/p>\n

$owner = “juneb”<\/p>\n

$result = $true<\/p>\n

Write-Verbose (“Created {0} by {1}. Result is {2}.” –f $filepath, $owner, $result)\nHere’s the result:<\/p>\n

VERBOSE: Created C:ps-testtest.txt by juneb. Result is True.\nThis statement uses string formatting<\/i>, that is, it creates a little template called a “format string” in the quoted string:<\/p>\n

“Created {0} by {1}. Result is {2}.”\nThe placeholders in the template are integers enclosed in curly braces. The integers must begin with 0 and increment by 1.<\/p>\n

{0}, {1}, {2} …\nYou can put the placeholders anywhere in the format string and use a placeholder multiple times in the same string.\nTo assign values to the placeholders, type -f<\/b> (for format<\/b>), and then type a comma-separated list of the values in the order that you want them to appear. The first value replaces the first placeholder {0} in the string, the second values replaces the {1}, and so on.\nAny valid expression can be a value.<\/p>\n

PS C:> “Created {0} on {1} by {2}. Result is {3} times {4}.” –f $filepath, [datetime]”1\/12\/2014″, $owner, “Success”, 14\/7<\/p>\n

Created C:ps-testtest.txt on 1\/12\/2014 12:00:00 AM by juneb. Result is Success times 2.\nYou can use string formatting anywhere in Windows PowerShell where a string value is permitted. When you use a formatted string as the value of the Message<\/b> parameter of Write-Verbose<\/b>, you must enclose it in parentheses. Otherwise, Windows PowerShell tries to interpret -f<\/b> as a parameter of Write-Verbose<\/b>.<\/p>\n

PS C:ps-test> Write-Verbose -Message “{0}” -f “Hi” -Verbose<\/p>\n

Write-Verbose : A parameter cannot be found that matches parameter name ‘f’.<\/p>\n

At line:1 char:30<\/p>\n

+ Write-Verbose -Message “{0}” -f “Hi” -Verbose<\/p>\n

+                              ~~<\/p>\n

    + CategoryInfo          : InvalidArgument: (:) [Write-Verbose], ParameterBindingException<\/p>\n

    + FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.PowerShell.Commands.WriteVerboseCommand<\/p>\n

PS C:ps-test> Write-Verbose -Message (“{0}” -f “Hi”) -Verbose<\/p>\n

VERBOSE: Hi\nThe critical element here is the cool -f<\/b>, which is the Windows PowerShell format<\/b> operator. It’s described briefly in about_Operators<\/a>, but the real info is on the following sites:<\/p>\n