PowerShell multiple string replacement efficiency

Question

I\'m trying to replace 600 different strings in a very large text file 30Mb+. I\'m current building a script that does this; following this Question:

Script:

Answer 1

I would use the powershell switch statement:

$string = gc $filePath 
$string | % {
    switch -regex ($_)  {
        'something0' { 'somethingelse0' }
        'something1' { 'somethingelse1' }
        'something2' { 'somethingelse2' }
        'something3' { 'somethingelse3' }
        'something4' { 'somethingelse4' }
        'something5' { 'somethingelse5' }
        'pattern(?\d+)' { $matches['a'] } # sample of more complex logic
   ...
   (600 More Lines...)
   ...
        default { $_ }
   }
} | ac "C:\log.txt"