Go: Find an element in a slice

Go has no generic search function for slices or arrays. It's straightforward to write your own linear search.

// Contains tells whether a contains x.
func Contains(a []string, x string) bool {
        for _, n := range a {
                if x == n {
                        return true
                }
        }
        return false
}

// Find returns the smallest index i at which x == a[i],
// or len(a) if there is no such index.
func Find(a []string, x string) int {
        for i, n := range a {
                if x == n {
                        return i
                }
        }
        return len(a)
}

More efficient alternatives

If the slice is sorted, the search can be performed more efficiently with a binary search.

If you are doing many searches, consider using a map instead.