code challenge AH 9

challenge9.swift

//"Challenge 9: Find pangrams
//Difficulty: Tricky
//
//Write a function that returns true if it is given a string that is an English pangram, ignoring letter case.
//
//Tip: A pangram is a string that contains every letter of the alphabet at least once.
//
//Sample input and output
//The string "The quick brown fox jumps over the lazy dog" should return true.
//The string "The quick brown fox jumped over the lazy dog" should return false, because it's missing the S.
//"
//
//Excerpt From: Paul Hudson. "Swift Coding Challenges." Apple Books.

import Foundation

func checkPangram(string: String) -> Bool {
    let lowerCasedString = string.lowercased()
    var dictionary : [Character: Int] = [:]
    let alphabet = "abcdefghijklmnopqrstuvwxyz"
    for character in lowerCasedString {
        guard alphabet.contains(character) else { continue }
        if dictionary[character] != nil {
            dictionary[character]! += 1
        } else {
            dictionary[character] = 1
        }
    }
    print(dictionary.count)
    if dictionary.count == 26 {
        return true
    } else {
        return false
    }
}

checkPangram(string: "The quick brown fox jumps over the lazy dog")
checkPangram(string: "The quick brown fox jumped over the lazy dog")