How to filter elements from an array made by spliting a string? [duplicate]

Question

When I do ($env:path).split(";"), there are many elements containing the string bin. I want to have a list of them. I try:

($env:path).split(";") | Where-Object {$_ -contains "bin" }

But there is no result. If I change the operator to -notcontains, it lists all paths, regardless of containing the string or not. How to make this works?

-contains is for an exact match on items of an array. what you want here is -match "bin" or -like "*bin*". — Santiago Squarzon
– Santiago Squarzon, Commented Mar 4 at 5:42
or ($env:path).split(";") | Where-Object {$_.contains("bin") } if you are looking for the C# string.contains() method — Daniel
– Daniel, Commented Mar 4 at 5:52
@Daniel you'd need to ToLower $_ or use the StringComparison overload in pwsh 7 for that to be a viable option. — Santiago Squarzon
– Santiago Squarzon, Commented Mar 4 at 5:53
Yes, there is an advantage of using operators as PowerShell has a very nice feature too: When the left-hand value in the comparison expression is a scalar value, the operator returns a Boolean value. When the left-hand value in the expression is a collection, the operator returns the elements of the collection that match the right-hand value of the expression which leads to the nice syntax: $env:path.split(";") -match 'bin' — iRon
– iRon, Commented Mar 4 at 7:19
-contains / -notcontains are collection operators: they test if the LHS object is equal in full to at least one element of the RHS collection. They are not to be confused with the .Contains() .NET method for substring matching. While PowerShell has no equivalent operator for literal substring matching, you can use -like with wildcard expressions or -match with regular expressions, both of which are case-insensitive by default. — mklement0
– mklement0, Commented Mar 4 at 18:22

sirtao · Accepted Answer · 2025-03-04 07:58:45Z

3

You are using the wrong comparison operator.

-contains checks if a Collection(array\list\etc) contains one specific element.

@('Z', 'A', 'Q', 'M') -contains 'A' returns $true

But you are working with the single strings of the array: you therefore need to use either -like(for simple wildcard matching) or -match(for regular expression matching)

so ($env:path).split(';') | Where-Object { $_ -match 'bin' }

Also, in more powershell-y way $env:path -split ';' | Where-Object { $_ -match 'bin' }

EDIT: and this is to go even further beyond! $env:path -split ';' -Match 'bin' (thanks @iRon)

(note I made the matching as simple as possible as example, you'll need to test if it works correctly for your needs)

More about Comparison Operators

edited Mar 4 at 7:58

answered Mar 4 at 7:35

sirtao

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6 Comments

Ooker Mar 4 at 7:38

it seems that the mindset of PowerShell is to use operators rather than methods, right?

sirtao Mar 4 at 12:06

@Ooker yeah, pretty much. The general idea is using the pipeline as much as possible(exceptions apply).

Ooker Mar 4 at 18:46

can you recommend any article that explains this in details?

Daniel Mar 4 at 21:20

learn.microsoft.com/en-us/powershell/scripting/learn/ps101/…

Ooker Mar 5 at 2:32

@Daniel that article doesn't seem to address the idea that operators have more advantages than methods in PS

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