Store and read a value — practice exercise

What you'll be asked to do

1. 1.Store and read a valueexercise · easy · 10 min

   Put a score in a Map and read it back.

   Passes when: #out should show 90.

2. 2.Count the entriesexercise · easy · 10 min · practice plan

   Report how many entries the Map holds.

   Passes when: #out should show 2.

3. 3.Use a number as a keyexercise · easy · 10 min · practice plan

   Store a value under a numeric key and read it back.

   Passes when: #out should show a number key.

4. 4.Remove an entryexercise · easy · 10 min · practice plan

   Delete an entry and report whether it is still there.

   Passes when: #out should show gone.

5. 5.Build from an array of pairsexercise · medium · 10 min · practice plan

   Create a Map from pairs and read one value.

   Passes when: #out should show 95.

6. 6.Fix the object used for a numeric keybug fix · easy · 8 min

   An object turns every key into a string.

   Passes when: #out should show a number key.

7. 7.Fix size called as a methodbug fix · easy · 8 min · practice plan

   size is a property, not a method.

   Passes when: #out should show 2.

8. 8.Fix bracket access on a Mapbug fix · easy · 8 min · practice plan

   A Map is read with get, not with square brackets.

   Passes when: #out should show 90.

9. 9.Fix the flat array passed inbug fix · easy · 8 min · practice plan

   A Map is built from pairs, not a flat list.

   Passes when: #out should show 95.

10. 10.Fix delete used with the valuebug fix · easy · 8 min · practice plan

    delete takes the key, not the value.

    Passes when: #out should show gone.

Between them these tasks cover Map, set and get and size.

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