Maps in Go

Key-value storage and the comma-ok idiom.

func mapBasics() (int, bool, int) {
    scores := map[string]int{"ada": 95, "grace": 88}
    scores["kay"] = 92

    ada := scores["ada"]
    value, ok := scores["alan"]
    delete(scores, "grace")

    total := 0
    for _, score := range scores {
        total += score
    }
    return ada, ok, total + value
}

How it works

1. A literal or assignment populates the map.
2. value, ok := m[k] reports whether the key existed.
3. delete removes; range iterates.

Keywords and builtins used here

• bool
• delete
• for
• func
• int
• map
• range
• return
• string

The run, in numbers

Lines

14

Characters to type

269

Tokens

78

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 52 seconds.

Type this snippet

Step 4 of 9 in Arrays, slices & maps, step 19 of 30 in Language basics.

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