check if a string contains only letters in Go

  s := "string"
  var valid bool
  valid = true
  for _, c := range s {
	if (c < 'a' || c > 'z') && (c < 'A' || c > 'Z') {
		valid = false
		break
	}
  }

This code uses a for loop to check all characters in the string variable s. For every character c that is found, it checks if the character is between a and z, or between A and Z. If any character is outside of this range, the boolean variable valid is set to false. If the loop runs to completion, valid will still be true. At the end, valid will have the value true if all characters were between a and z, or A and Z, and false otherwise.