Deleting map entries in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

How do you delete an entry from a map in Go?

Use the built-in delete function with the map and the key you want to remove. For example: delete(myMap, key).

beginner

What happens if you try to delete a key that does not exist in a Go map?

Nothing happens. The delete function does not cause an error if the key is missing; it simply does nothing.

intermediate

Can you delete entries from a nil map in Go?

No. Deleting from a nil map does nothing and does not cause a runtime panic. You must ensure the map is initialized before adding or deleting entries.

beginner

What is the syntax of the delete function in Go?

The syntax is: delete(mapVariable, key). It takes two arguments: the map and the key to remove.

beginner

Why might you want to delete entries from a map in Go?

To free up memory, remove outdated or unwanted data, or keep the map clean and efficient.

What does the delete function do in Go?

A Deletes the entire map

B Removes a key and its value from a map

C Clears all values but keeps keys

D Copies a map to another variable

The delete function removes a specific key and its associated value from a map.

What happens if you delete a key that does not exist in a Go map?

A Runtime error occurs

B The key is added with a zero value

C Nothing happens, no error

D The map is cleared

Deleting a non-existent key does nothing and does not cause an error.

Which of these is the correct way to delete a key named 'id' from a map called 'users'?

A delete(users, "id")

B users.remove('id')

C users.delete('id')

D remove(users, 'id')

The correct syntax is delete(users, "id").

What will happen if you try to delete a key from a nil map in Go?

A It deletes the key safely

B It causes a runtime panic

C It initializes the map automatically

D It returns an error

Deleting from a nil map does nothing and does not cause a runtime panic.

Why is deleting entries from a map useful?

A To convert the map to a slice

B To add new keys

C To sort the map

D To free memory and remove unwanted data

Deleting entries helps free memory and keep the map clean by removing unwanted data.

Explain how to delete an entry from a map in Go and what happens if the key does not exist.

Think about the built-in function that removes keys.

Describe what happens if you try to delete a key from a nil map in Go and why.

Consider what happens when you use a map that has not been created yet.