Why maps are used in Go - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a map that stores string keys and int values.

Go

var ages [1]

Drag options to blanks, or click blank then click option'

A[]int

Bmap[string]int

Cstruct{}

Dchan int

Attempts:

3 left

💡 Hint

Common Mistakes

Using slice syntax instead of map syntax.

Trying to declare a map without specifying key and value types.

Maps in Go are declared using the map[keyType]valueType syntax. Here, map[string]int means keys are strings and values are integers.

2fill in blank

medium

Complete the code to initialize a map using the make function.

Go

scores := [1](map[string]int)

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Amake

Bcreate

Cnew

Dinit

Attempts:

3 left

💡 Hint

Common Mistakes

Using new instead of make for maps.

Trying to initialize maps without using make or a literal.

The make function is used to create and initialize maps in Go. It allocates memory for the map.

3fill in blank

hard

Fix the error in the code to correctly add a key-value pair to the map.

Go

m := make(map[string]int)
m[[1]] = 10

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Am

Bage

C10

D"age"

Attempts:

3 left

💡 Hint

Common Mistakes

Using an integer or variable without quotes as a string key.

Using the map variable itself as a key.

Map keys must be of the declared key type. Since the key type is string, the key must be a string literal like "age".

4fill in blank

hard

Fill both blanks to create a map comprehension that stores word lengths for words longer than 3 characters.

Go

lengths := map[string]int{
	[1]: len([2]) for _, [2] := range words if len([2]) > 3
}

Drag options to blanks, or click blank then click option'

A"word"

Bword

Cwords

Dlen

Attempts:

3 left

💡 Hint

Common Mistakes

Using the slice words as a key.

Not quoting the key string.

In Go, map literals don't support comprehensions like Python. This task is a trick to think about keys and values: keys are strings (words), so use "word" as a key placeholder and word as the variable holding each word.

5fill in blank

hard

Fill all three blanks to check if a key exists in the map and print its value.

Go

if val, [1] := m[[2]]; [3] {
	fmt.Println(val)
}

Drag options to blanks, or click blank then click option'

Aok

B"key"

Dval

Attempts:

3 left

💡 Hint

Common Mistakes

Using the value variable instead of the boolean check.

Not quoting the key string.

In Go, to check if a key exists in a map, you use the two-value assignment: val, ok := m["key"]. Then you check if ok is true.