[powershell] PowerShell and the -contains operator

Consider the following snippet:

"12-18" -Contains "-"

You’d think this evaluates to true, but it doesn't. This will evaluate to false instead. I’m not sure why this happens, but it does.

To avoid this, you can use this instead:

"12-18".Contains("-")

Now the expression will evaluate to true.

Why does the first code snippet behave like that? is there something special about - that doesn't play nicely with -Contains? The documentation doesn't mention anything about it.

• like is best, or at least easiest.
• match is used for regex comparisons.

Reference: https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_comparison_operators?view=powershell-6

You can use like:

"12-18" -like "*-*"

Or split for contains:

"12-18" -split "" -contains "-"

-Contains is actually a collection operator. It is true if the collection contains the object. It is not limited to strings.

-match and -imatch are regular expression string matchers, and set automatic variables to use with captures.

-like, -ilike are SQL-like matchers.