Dictionary Length in Go

In Go, you can get the number of key-value pairs in a map using the built-in len() function:

scores := map[string]int{}
scores["Alice"] = 95
scores["Bob"] = 87
scores["Charlie"] = 72

n := len(scores)
fmt.Println(n)  // 3

len() returns the number of entries. You can also check if it's empty by comparing to zero:

fmt.Println(len(scores) == 0)  // false
empty := map[string]int{}
fmt.Println(len(empty))    // 0