Classify file extension and applying logic

问题

Need to execute logic depending on the file extension.

Input: $FileName = "ABC.tar.gz.manifest" or "ABC.tar.gz" or "ABC.zip"

$EXTZ = ".zip"
$EXTGZ = "tar.gz"
$EXT = $FileName -match "$EXTZ"

$EXT
if ($EXT = 'True') {
    Write-Host "$EXTZ"
} elseif ($EXT = 'False') {
   Write-Host "$EXTGZ"
}

But the problem is some files are having the double extension. How we can solve this?

If the extension is .zip need to print "ABC".

If the file extension is .tar.gz or .tar.gz.manifest need to print "XYZ".

回答1:

You can check if the $fileInfo contains the extension (you have a problem in the if, in PowerShell you can't do =, you do -eq):

$Filename = "ABC.tar.gz.manifest"
$EXTGZ = "tar.gz"
$EXT = $Filename.Contains($EXTGZ)
if($EXT -eq $true)
{
   # Do Something
}

回答2:

I'd use a Regular Expression and a switch instead of multiple if commands

## Q:\Test\2019\05\27\SO_56322763.ps1

foreach ($FileName in ("ABC.tar.gz.manifest","ABC.tar.gz","ABC.zip","foo.bar")){
    "`$FileName is: {0}" -f $FileName

    switch -regex ($FileName){
        "\.tar\.gz(\.manifest)?$" {"XYZ";Break}
        "\.zip$"                  {"ABC";Break}
        default                   {"anything"}
    }
}

Sample output:

> Q:\Test\2019\05\27\SO_56322763.ps1
$FileName is: ABC.tar.gz.manifest
XYZ
$FileName is: ABC.tar.gz
XYZ
$FileName is: ABC.zip
ABC
$FileName is: foo.bar
anything

来源：https://stackoverflow.com/questions/56322763/classify-file-extension-and-applying-logic