Range: Iterating Over Collections

Snippet

Range: Iterating Over Collections

The range keyword provides a clean way to iterate over slices, arrays, maps, and channels. For slices and arrays, it returns both the index and the value. For maps, it returns the key and value. You can ignore unwanted values using the blank identifier _.

snippet.go
go
package main
import "fmt"
 
func main() {
	colors := []string{"Red", "Green", "Blue"}
 
	for index, value := range colors {
		fmt.Printf("%d: %s\n", index, value)
	}
 
	ages := map[string]int{"Max": 25, "Anna": 30}
	for name, age := range ages {
		fmt.Println(name, "is", age)
	}
}

Breakdown

for index, value := range colors {

Range returns index and copy of each element

fmt.Printf("%d: %s\n", index, value)

Prints formatted output with index and value

for name, age := range ages {

Range over map returns key and value pairs

_ = index

Blank identifier discards unwanted index

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Range: Iterating Over Collections

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