How can I check if a string is null or empty in PowerShell?

Question

Is there a built-in IsNullOrEmpty-like function in order to check if a string is null or empty, in PowerShell?

I could not find it so far and if there i

Answer 1

PowerShell 2.0 replacement for [string]::IsNullOrWhiteSpace() is string -notmatch "\S"

("\S" = any non-whitespace character)

> $null  -notmatch "\S"
True
> "   "  -notmatch "\S"
True
> " x "  -notmatch "\S"
False

Performance is very close:

> Measure-Command {1..1000000 |% {[string]::IsNullOrWhiteSpace("   ")}}
TotalMilliseconds : 3641.2089

> Measure-Command {1..1000000 |% {"   " -notmatch "\S"}}
TotalMilliseconds : 4040.8453