code challenge AH

challenge7.swift

"Challenge 7: Condense whitespace
Difficulty: Easy

Write a function that returns a string with any consecutive spaces replaced with a single space.

Sample input and output
I've marked spaces using "[space]" below for visual purposes:

The string "a[space][space][space]b[space][space][space]c" should return "a[space]b[space]c".
The string "[space][space][space][space]a" should return "[space]a".
The string "abc" should return "abc"."

Excerpt From: Paul Hudson. "Swift Coding Challenges." Apple Books. 



import Foundation

func condenseWhiteSpace(string: String) -> String {
    var subStringArray: [String] = []
    let index = string.index(string.startIndex, offsetBy: 0)
    if string[index] == " " {
        subStringArray.append(" ")
    }
    let subStrings = string.split(separator: " ")
    for subString in subStrings {
        let subStringString = String(subString)
        subStringString.replacingOccurrences(of: " ", with: "")
        subStringArray.append(subStringString)
    }
    let indexEnd = string.index(string.endIndex, offsetBy: -1)
    if string[indexEnd] == " " {
        subStringArray.append(" ")
    }
    return subStringArray.joined(separator: " ")
}

condenseWhiteSpace(string: "a   b   c")
condenseWhiteSpace(string: "    a")
condenseWhiteSpace(string: "abc")
condenseWhiteSpace(string: "a    ")