Problems using .substring method

Question

_{Thursday, September 15, 2011 7:08 AM}

Hi,

I am trying to make a script that will get a list of files and then manipulate the results to just take the first 8 characters.

$List = get-childitem "C:\windows"

$List |Format-Wide -Column 1 -property name

ForEach($File In $List)
{

write-host $File

$First8=$File.substring(0,7)

write-host $First8

} 

When I run the script I get the error 

Method invocation failed because [System.IO.FileInfo] doesn't contain a method
named 'substring'.
At ListFiles003.ps1:12 char:27

• $First8=$Package.substring <<<< (0,7)
      + CategoryInfo          : InvalidOperation: (substring:String) [], Runtime
     Exception
      + FullyQualifiedErrorId : MethodNotFound
   

I understand that the object $package is not a string which is why the  .substring method is failing.

I don't know how to convert each $file to a string so that I can use the substring method.

Any ideas?

All replies (4)

_{Thursday, September 15, 2011 7:44 AM ✅Answered | 1 vote}

Try this: $First8 = $file.Name.Substring(0,7)

Note that this will fail if the name is shorter then 8 characters.

_{Thursday, September 15, 2011 7:59 AM ✅Answered | 1 vote}

I'll try to explain whats wrong.

The line "$First8=$File.substring(0,7)" will not work, because $File is a type file item, not a string.  You can only use 'substring' on strings.  In addition to this, not all filenames have 8 characters, so a filename like 1234.txt would not be changed.

The answer lies in using the basename property, as such:

$List = get-childitem "C:\windows"

$List |Format-Wide -Column 1 -property name

foreach ($File in $List)
{
Write-Host $File
$First8 = $File.basename
Write-Host $First8
}

[string](0..9|%{[char][int](32+("39826578840055658268").substring(($_*2),2))})-replace "\s{1}\b"

_{Thursday, September 15, 2011 9:08 AM}

You can also use the join parameter. Then it doesn't matter if the string isn't long enough.

$First8 = $File.Name[0..7] -join ""

[0..7] will return an array with all chars as an seperate record.

-Join "" will make a string of this array.

_{Thursday, September 15, 2011 10:14 AM}

Thanks a lot BigTeddy and VincentK!