Local Variable Declarations

Short variable declarations (:=) should be used if a variable is being set to some value explicitly.

Bad	Good
var s = "foo"	s := "foo"

However, there are cases where the default value is clearer when the var keyword is used. Declaring Empty Slices, for example.

Bad

Good

func f(list []int) {
  filtered := []int{}
  for _, v := range list {
    if v > 10 {
      filtered = append(filtered, v)
    }
  }
}

func f(list []int) {
  var filtered []int
  for _, v := range list {
    if v > 10 {
      filtered = append(filtered, v)
    }
  }
}