PowerShell Basics -Contains, -CContains & -NotContains Conditional Operators

PowerShell Basics_ -Contains

Windows PowerShell -Contains

When it comes filtering, or finding data we are spoilt for choice with -Match, -Like and -Contains.  While there is overlap, each conditional operator has a distinctive role in PowerShell scripting.

-Contains is best for seeking an exact value.  If I want a command to return either True or False, I start with -Contains, whereas, if I want a list of results then I try -Match or -Like.

Topics for PowerShell’s -Contains Conditional Operator

Example 1a: PowerShell -Contains

PowerShell uses singular nouns; thus “contains” is a verb, and not a plural noun.  A feature of -Contains is that usually returns “True” or “False.  If you are looking for a command to return a list of values, then employ -Match or -Like.

# PowerShell -Contains Operator
$ArraySimple =@("House","Flat","Bungalow")
$ArraySimple -Contains "Flat"

# Result PS> True

Example 1b: PowerShell’s -Contains is Very Strict

-Contains can be frustrating because it’s so picky.  After a while you realize that this just a design feature, if you don’t like it, try -Match.

# PowerShell -Contains Operator
$ArraySimple =@("House","Flats","Bungalow")
$ArraySimple -Contains "Flat"

# Result PS> False

Note 1: -Contains interprets “Flats” and “Flat” as different, thus returns False; it does not matter that Flat is a subset of Flats.

Challenge: Substitute -Match for -Contains.

Guy Recommends: Free WMI Monitor for PowerShell (FREE TOOL)Solarwinds Free WMI Monitor for PowerShell

Windows Management Instrumentation (WMI) is one of the hidden treasures of Microsoft’s operating systems.  Fortunately, SolarWinds have created a Free WMI Monitor for PowerShell so that you can discover these gems of performance information, and thus improve your PowerShell scripts.

Take the guesswork out of which WMI counters to use when scripting the operating system, Active Directory, or Exchange Server. Give this WMI monitor a try – it’s free.

SolarWinds WMI Monitor Download 100% Free Tool

Example 2: Seeking a Value in a Collection

-Contains would be my choice of conditional operators for situations where I wanted to test for one particular item in a collection, array or a hashtable.

# PowerShell -Contains
$Collection = "Peter Smith", "Paula Harris", "Joan Evans"
$Collection -Contains "Paula"

# Result PS> False

Note 2: If you coded: $Collection -Contains “Paula Harris”
The result would be: True.  You need an exact match of the full item.

Note 3: $Collection -Contains “Paula*” does not help.  Wildcards are next to useless with -Contains.  Better: try -Match Paula, or -Like Paula*

Example 3: PowerShell -Contains SpreadsheetPowerShell -Contains

Let us assume we wish to search in a file called links.csv.  Furthermore, we can use Import-Csv to read the data so that we can test values with -Contains.

My spreadsheet is called links.csv
I stored the file in D:\PowerShell
The column name is “Custom channel”
See screenshot to the right.

# PowerShell -Contains Operator
$File = "D:\Powershell\links.csv"
$Check = (Import-Csv $File)."Custom channel"
$Check -Contains "linktop"

# Result PS> True

Guy Recommends:  Network Performance Monitor (FREE TRIAL)Review of Orion NPM v11.5

SolarWinds Network Performance Monitor (NPM) will help you discover what’s happening on your network.  This utility will also guide you through troubleshooting; the dashboard will indicate whether the root cause is a broken link, faulty equipment or resource overload.

What I like best is the way NPM suggests solutions to network problems.  Its also has the ability to monitor the health of individual VMware virtual machines.  If you are interested in troubleshooting, and creating network maps, then I recommend that you try NPM on a 30-day free trial.

SolarWinds Network Performance Monitor Download 30-day FREE Trial

Example 4: PowerShell -CContains

As with PowerShell’s other conditional operators, you can force them to be case sensitivity by preceding the command with a ‘C’; CContains is not a typo!

# PowerShell -Contains Operator
$File = "D:\Powershell\links.csv"
$Check = (Import-Csv $File)."Custom channel"
$Check -CContains "linktop"

# Result PS> False

Note 4: The point is that in the spreadsheet the value is clearly ‘LinkTop’, when we force case-sensitivity with CContains, this is not the same as ‘linktop’, hence a False result.

Example 5: PowerShell -NotContains

The negative -NotContains is not as useful as -NotMatch.  However, from what we have already learned the syntax is predictable.

# PowerShell -Contains Operator
$File = "D:\Powershell\links.csv"
$Check = (Import-Csv $File)."Custom channel"
$Check -NotContains "link"

# Result PS> True

Note 5: Remember that with -Contains, and by extension -NotContains, the match has to be exact.  There is no ‘Custom channel’ with the name of precisely ‘link’.

See more on PowerShell’s -Like comparisons »

Guy Recommends: SolarWinds Engineer’s Toolset (FREE TRIAL)Engineer's Toolset v10

This Engineer’s Toolset provides a comprehensive console of 50 utilities for troubleshooting computer problems.  Guy says it helps me monitor what’s occurring on the network, and each tool teaches me more about how the underlying system operates.

There are so many good gadgets; it’s like having free rein of a sweetshop.  Thankfully the utilities are displayed logically: monitoring, network discovery, diagnostic, and Cisco tools.  Try the SolarWinds Engineer’s Toolset on a 14-day free trial now!

SolarWinds Engineer's Toolset Download 14-day FREE Trial


# For even more information about PowerShell Operators try:

Get-Help about_Operators

Here is the List of the Types of PowerShell’s Operators

  • Arithmetic (+ * – /)
  • Assignment (= also -= +=)
  • Comparison ( -Match and -Like; also: -eq -gt)
  • Logical ( -And -Not)
  • Redirectional ( > )
  • Split and Join ( -split)
  • Type (-Is -Isnot)
  • Unary ($i++)

See also PowerShell’s -Match »

Summary of PowerShell’s -Contains Conditional Operator

When you seek an exact value, then -Contains would be my first choice of conditional operator.  -Match or -Like are better suited to scenarios where you only need a partial match, or you need a list of items.

See more Windows PowerShell flow control examples

PowerShell Home  • PowerShell If Statement  • PowerShell ElseIf   • Free Permissions Analyzer

Conditional Operators  • PowerShell -Match  • PowerShell -Like  • PowerShell -Contains

PowerShell Comparison Operators  • PowerShell Syntax   • Where Filter  • PowerShell Else

Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.