go

From this answer:

  import (
      "fmt"
      "regexp"
      "strings"
  )

  const (
      str    = "something"
      substr = "some"
  )

  // 1. Contains
  res := strings.Contains(str, substr)
  fmt.Println(res) // true

  // 2. Index: check the index of the first instance of substr in str, or -1 if substr is not present
  i := strings.Index(str, substr)
  fmt.Println(i) // 0

  // 3. Split by substr and check len of the slice, or length is 1 if substr is not present
  ss := strings.Split(str, substr)
  fmt.Println(len(ss)) // 2

  // 4. Check number of non-overlapping instances of substr in str
  c := strings.Count(str, substr)
  fmt.Println(c) // 1

  // 5. RegExp
  matched, _ := regexp.MatchString(substr, str)
  fmt.Println(matched) // true

  // 6. Compiled RegExp
  re = regexp.MustCompile(substr)
  res = re.MatchString(str)
  fmt.Println(res) // true

Option two easily solves this problem.