Common regex patterns in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell regex match?

Given the string 'Contact: [e-mail]', what will be the output of this command?

$string = 'Contact: [e-mail]' if ($string -match '\b\w+@\w+\.\w+\b') { $matches[0] }

PowerShell

$string = 'Contact: [e-mail]'
if ($string -match '\b\w+@\w+\.\w+\b') { $matches[0] }

A [e-mail]

B Contact

C example.com

D No match

💡 Hint

Look for the pattern that matches an email format.

The regex matches a simple email pattern. The matched substring is '[e-mail]'.

💻 Command Output

intermediate

What does this regex extract from the date string?

Given the string 'Date: 2024-06-15', what will this command output?

$date = 'Date: 2024-06-15' if ($date -match '(\d{4})-(\d{2})-(\d{2})') { "$($matches[1])/$($matches[2])/$($matches[3])" }

PowerShell

$date = 'Date: 2024-06-15'
if ($date -match '(\d{4})-(\d{2})-(\d{2})') { "$($matches[1])/$($matches[2])/$($matches[3])" }

A No match

B Date

C 06-15-2024

D 2024/06/15

💡 Hint

The regex captures year, month, and day in groups.

The regex captures the year, month, and day parts separately and outputs them in YYYY/MM/DD format.

📝 Syntax

advanced

Which regex pattern matches a US phone number format?

Which option correctly matches a US phone number like [phone] in PowerShell regex?

A \d{3}-\d{3}-\d{4}

B \(\d{3}\) \d{3}-\d{4}

C \(\d{3}\)\d{3}-\d{4}

D \(\d{3}\) \d{3} \d{4}

💡 Hint

Look for the pattern with parentheses, space, and dash in correct places.

Option B matches the exact format with parentheses around area code, a space, then three digits, a dash, and four digits.

🔧 Debug

advanced

Why does this regex fail to match an IP address?

This PowerShell code tries to match an IP address but fails:

$ip = '192.168.1.1' if ($ip -match '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}') { 'Match' } else { 'No match' }

Why does it fail?

A The dot (.) is not escaped, so it matches any character.

B The regex pattern is missing anchors ^ and $.

C The backslashes are not escaped properly in the regex string.

D The quantifiers {1,3} are invalid in PowerShell regex.

💡 Hint

Check how backslashes are handled in PowerShell strings.

In PowerShell, backslashes must be escaped in double-quoted strings or use single quotes. Here, the pattern uses single quotes but the backslash before dot is not doubled, so it is treated literally.

🚀 Application

expert

Extract all hashtags from a tweet using PowerShell regex

You have this tweet string:

$tweet = 'Learning #PowerShell and #regex is fun! #automation'

Which PowerShell command extracts all hashtags as an array?

A [regex]::Matches($tweet, '#\w+').ForEach({ $_.Value })

B [regex]::Matches($tweet, '#\w+').Value

C ([regex]::Matches($tweet, '#\w+')).Value

D [regex]::Matches($tweet, '#\w+').Cast().Select({ $_.Value })

💡 Hint

Look for a method to iterate over matches and extract their values.

Option A uses ForEach to iterate over the MatchCollection and extract the Value property of each match, returning an array of hashtags.