Go: Different ways of iterating over an Array and Slice

Go provides many different ways of iterating over an array. All examples below are also applicable to slice.

Let’s define an array of letters first

letters := []string{"a", "b", "c", "d", "e"}

Using the range operator

• With index and value

for i, letter := range letters {
   fmt.Printf("%d %s\n", i, letter)
}

• Only Value

for _, letter := range letters {
   fmt.Println(letter)
}

• Only index

for i := range letters {
   fmt.Println(i)
}

• Without value and index. Just print array values

i := 0
for range letters {
  fmt.Println(i)
  i++
}

Using Only For operator

• Single initialization and post

len := len(letters)
for i := 0; i < len; i++ {
  fmt.Println(letters[i])
}

• Multiple initialization and post statement

len := len(letters)
for i, j := 0, len; i < j; i, j = i+1, j-1 {
  fmt.Println(letters[i])
}