Match operator (=~) in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Ruby match operator =~ do?

It checks if a string matches a pattern defined by a regular expression. It returns the index of the first match or nil if no match is found.

beginner

What is the return value of "hello" =~ /e/ in Ruby?

It returns 1 because the letter 'e' is found at index 1 in the string "hello".

beginner

What does the match operator =~ return if there is no match?

It returns nil, which means no match was found in the string.

beginner

How can you use the match operator =~ in an if statement?

You can write if string =~ /pattern/ to check if the pattern exists in the string. If it matches, the condition is true; otherwise, false.

intermediate

What is the difference between =~ and match method in Ruby?

=~ returns the index of the match or nil. The match method returns a MatchData object with detailed info about the match.

What does "cat" =~ /a/ return in Ruby?

A nil

B 1

C 0

D true

The letter 'a' is at index 1 in "cat", so the match operator returns 1.

What is the result of "dog" =~ /z/?

A 0

B false

C nil

D -1

No 'z' in "dog", so the match operator returns nil.

Which of these is true about the match operator =~?

A Returns index of match or nil

B Returns true or false

C Returns the matched string

D Returns a boolean and the matched string

It returns the index where the match starts or nil if no match.

How can you check if a string contains digits using =~?

A string =~ /\d/

B string =~ /[a-z]/

C string =~ /\w/

D string =~ /\s/

The regex /\d/ matches any digit character.

What does if str =~ /pattern/ do in Ruby?

A Never runs code

B Runs code if pattern is not found

C Always runs code

D Runs code if pattern is found

The condition is true if the pattern matches the string.

Explain how the Ruby match operator =~ works with strings and regular expressions.

Think about what happens when you look for a pattern inside a word.

Describe how you would use the match operator =~ inside an if statement to check for a pattern.

Remember how Ruby treats nil in conditions.