Regex quantifiers and anchors in PowerShell - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the regex quantifier * mean?

The * quantifier means "match zero or more occurrences" of the preceding character or group. For example, a* matches '', 'a', 'aa', 'aaa', and so on.

beginner

What is the difference between + and ? quantifiers in regex?

+ means "one or more occurrences" while ? means "zero or one occurrence" of the preceding element. For example, a+ matches 'a', 'aa', 'aaa', but not ''. a? matches '' or 'a'.

beginner

What does the anchor ^ do in a regex pattern?

The ^ anchor matches the start of a string. For example, ^Hello matches 'Hello world' but not 'Say Hello'.

beginner

What does the anchor $ do in a regex pattern?

The $ anchor matches the end of a string. For example, world$ matches 'Hello world' but not 'world peace'.

beginner

In PowerShell, how would you check if a string starts with 'Test' using regex anchors?

You can use the -match operator with the pattern ^Test. For example: 'Test string' -match '^Test' returns True because the string starts with 'Test'.

What does the regex quantifier ? mean?

A One or more occurrences

B Zero or more occurrences

C Zero or one occurrence

D Exactly one occurrence

The ? quantifier matches zero or one occurrence of the preceding element.

Which regex anchor matches the end of a string?

A ^

B $

C \b

D \A

The $ anchor matches the end of a string.

In PowerShell, which operator is used to test if a string matches a regex pattern?

A -match

B -eq

C -contains

D -like

The -match operator tests if a string matches a regex pattern.

What does the regex quantifier + require at minimum?

A Optional occurrence

B Zero occurrences

C Two occurrences

D One occurrence

The + quantifier requires at least one occurrence of the preceding element.

What does the regex pattern ^abc$ match?

A Strings exactly equal to 'abc'

B Strings starting with 'abc'

C Strings ending with 'abc'

D Any string containing 'abc'

The pattern ^abc$ matches strings that are exactly 'abc' with nothing before or after.

Explain how regex quantifiers *, +, ? differ and give a simple example for each.

Think about how many times the character can appear.

Describe how anchors ^ and $ help in matching patterns in strings.

Anchors fix the position in the string where the match must occur.