String replacement

A question of the forum involved changing the file path for a folder. The original path was like this

$folder = "C:\FolderName\NextFolder\ThirdFolder"

The first attempt uses the –replace operator

PS> $newfolder = $folder -replace "C:\FolderName\", "D:\"
Invalid regular expression pattern: C:\FolderName\.
At line:1 char:30
+ $newfolder = $folder -replace <<<<  "C:\FolderName\", "D:\"
    + CategoryInfo          : InvalidOperation: (C:\FolderName\:String) [], RuntimeException
    + FullyQualifiedErrorId : InvalidRegularExpression

The way to get round this is to escape the \ with another \ to keep the regular expressions happy

PS> $newfolder = $folder -replace "C:\\FolderName\\", "D:\"
PS> $newfolder
D:\NextFolder\ThirdFolder

Alternatively if you don’t care about happy regex then use the Replace() method of the string class

PS> $newfolder = $folder.Replace("C:\FolderName\", "D:\")
PS> $newfolder
D:\NextFolder\ThirdFolder

Its simpler than dealing with regex and escaping characters to meet its quirks