Let’s define a map first

sample := map[string]string{
        "a": "x",
        "b": "y",
}

• Iterating over all keys and values

for k, v := range sample {
   fmt.Printf("key :%s value: %s\n", k, v)
}

Output:

key :a value: x
key :b value: y

• Iterating over only keys

for k := range sample {
   fmt.Printf("key :%s\n", k)
}

Output:

key :a
key :b

• Iterating over only values

for _, v := range sample {
   fmt.Printf("value :%s\n", v)
}

Output:

value :x
value :y

• Get list of all keys

keys := getAllKeys(sample)
fmt.Println(keys)

func getAllKeys(sample map[string]string) []string {
    var keys []string
    for k := range sample {
        keys = append(keys, k)
    }
    return keys
}

Output:

[a b]

The post Different ways of iterating over a map in Go (Golang) appeared first on Welcome To Golang By Example.

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])
}

The post Go: Different ways of iterating over an Array and Slice appeared first on Welcome To Golang By Example.