iOS Closures in Swift First Class Functions Higher Order Functions

Joey Liu
Joey Liu
3,982 Points

Immutable value 'counter' was never used; consider replacing with '_' or removing it

I don't know why counter in the internal for loop would cause such a problem and I am stuck

functions.swift
// Enter your code below

extension String{
 func  transform(_ transforming: (String) -> String) -> String{

  return transforming(self)
}
}

func removeVowels(from: String) -> String{
    let word:[Character] = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"]
    let characterInput = Array(from)
    var characterOutput = ""
    for counter in 0...word.count {
      for counter in 0...characterInput.count{
      if characterInput[counter] == word[counter] {
        characterOutput.append(word[counter])
      }
     }
    }
  return characterOutput
}