Regex quantifiers and anchors in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell regex match?

Consider the following PowerShell command that uses regex anchors and quantifiers. What will be the output?

PowerShell

$text = 'abc123xyz'
if ($text -match '^abc\d{3}xyz$') { 'Match' } else { 'No Match' }

A False

B No Match

C SyntaxError

D Match

💡 Hint

The regex checks if the entire string matches the pattern from start (^) to end ($).

The regex ^abc\d{3}xyz$ means the string must start with 'abc', followed by exactly 3 digits, then 'xyz' and nothing else. The string 'abc123xyz' matches this exactly, so output is 'Match'.

💻 Command Output

intermediate

What does this regex extract from the string?

Given this PowerShell command, what will be the output?

PowerShell

$text = 'Error: 404 Not Found'
if ($text -match 'Error: (\d{3})') { $matches[1] } else { 'No match' }

A 404

B Error

C No match

D SyntaxError

💡 Hint

The regex captures exactly three digits after 'Error: '.

The regex 'Error: (\d{3})' matches 'Error: ' followed by exactly 3 digits. The digits are captured in group 1, so $matches[1] returns '404'.

💻 Command Output

advanced

What is the output of this regex with greedy quantifier?

What will this PowerShell command output?

PowerShell

$text = 'abc123xyz456'
if ($text -match 'abc.*xyz') { $matches[0] } else { 'No match' }

A abc123xyz

B abc123xyz456

C No match

D SyntaxError

💡 Hint

The .* is greedy and matches as many characters as possible but stops at the last 'xyz'.

The regex 'abc.*xyz' matches 'abc' followed by any characters (.*) greedily until the last 'xyz'. It matches 'abc123xyz' because 'xyz456' does not match the pattern fully. So output is 'abc123xyz'.

💻 Command Output

advanced

What error does this regex cause in PowerShell?

What error will this command produce?

PowerShell

$text = 'abc123'
if ($text -match '[a-z{3}') { 'Match' } else { 'No Match' }

A No Match

B Match

C SyntaxError

D RuntimeException

💡 Hint

Check if the regex pattern is valid with balanced brackets.

The regex pattern '[a-z{3}' is invalid because the character class is not closed with a ']'. This causes a syntax error in regex parsing.

💻 Command Output

expert

What is the output of this complex regex with anchors and quantifiers?

Analyze this PowerShell command and determine its output.

PowerShell

$text = 'start123end'
if ($text -match '^(start)(\d+)(end)$') { "$($matches[1])-$($matches[2])-$($matches[3])" } else { 'No match' }

A No match

B start-123-end

C start123end

D SyntaxError

💡 Hint

The regex uses anchors to match the whole string and captures three groups.

The regex ^(start)(\d+)(end)$ matches the entire string starting with 'start', then one or more digits, then 'end'. It captures these three parts in groups 1, 2, and 3. The output joins them with dashes: 'start-123-end'.