Match one or more digits — practice exercise

What you'll be asked to do

1. 1.Match one or more digitsexercise · easy · 10 min

   Pull the whole number out of the text.

   Passes when: #out should show 42.

2. 2.Group runs of charactersexercise · easy · 10 min · practice plan

   Find every run of digits and join them.

   Passes when: #out should show 1,22,333.

3. 3.Make a letter optionalexercise · easy · 10 min · practice plan

   Match both spellings of the colour word.

   Passes when: #out should show both spellings.

4. 4.Require an exact countexercise · easy · 10 min · practice plan

   Check the value is exactly four digits.

   Passes when: #out should show a valid year.

5. 5.Match lazilyexercise · medium · 10 min · practice plan

   Use a lazy quantifier to stop at the first closing bracket.

   Passes when: #out should show <a>.

6. 6.Fix the missing quantifierbug fix · easy · 8 min

   Without a plus only one digit is matched.

   Passes when: #out should show 42.

7. 7.Fix the greedy matchbug fix · easy · 8 min · practice plan

   A greedy quantifier swallows both tags instead of stopping at the first.

   Passes when: #out should show 3 characters.

8. 8.Fix the star used where plus is neededbug fix · easy · 8 min · practice plan

   A star allows zero characters, so empty text passes.

   Passes when: #out should show rejected.

9. 9.Fix the wrong exact countbug fix · easy · 8 min · practice plan

   A year needs four digits, not three.

   Passes when: #out should show a valid year.

10. 10.Fix the optional marker on the wrong characterbug fix · easy · 8 min · practice plan

    The u is the optional letter, not the r.

    Passes when: #out should show both spellings.

Between them these tasks cover Quantifiers, Greedy matching and Lazy matching.

Looking for a different chapter? See every practice set, or switch to the interview theory questions.