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iOS

Posted by Rani Shayto
Rani Shayto
769 Points

Creating a function that returns either a title or an artist from a defined Dictionary in the output form of True/False

Questions are in the code as comments:

//: Playground - noun: a place where people can play

import UIKit

func nowPlaying (#songInfo: String) -> (Bool) {

let song1 = ["title":"Snow", "artist":"Rani"]

let x = song1["title"]

let y = song1["artist"]

var found = false

for x in song1 {

    if x == songInfo {

    found = true
    }

    else if y == songInfo {
        found = true


    } else {

    found = false

    }

}

return found
}

nowPlaying(songInfo: "Rani")

//I want to create the function nowPlaying for which I can input either the title or the artist of my song1 dictionary. If what I input into the function is in fact found in my dictionary, I want a boolian return of True, indicating I do have the information (either the title or the artist) in my song1 dictionary. Otherwise, I want the function to return a false, indicating that I do not have such information (either title or artist) in my song1 dictionary

//Error: line 15: Binary operator '==' cannot be applied to operands of type "(String,String)" and 'String

Rani Shayto
Rani Shayto
769 Points

Edit: since the line numbers don't show above, the error I got is for the line "if x == songInfo {

2 Answers

James Attree
James Attree
7,906 Points

The error is quite descriptive, it's saying that you can't compare a (String, String) to a (String). When you type:

let x = song1["title"]

x is actually (title, Snow)

When you try to compare this to the String "Rani" it will give you that error because the types are different. You need to find a way to loop through the dictionary. You can do this with a for:

for (title, artist) in song1 {
  // Inside here, you have access to both the title and the artist as a string
}

func nowPlaying (#songInfo: String) -> (Bool) {
    let song1 = ["title":"Snow", "artist":"Rani"]

    for (title, artist) in song1 {
        if (title == songInfo) {
            return true
        } else if (artist == songInfo) {
            return true
        }
    }
    return false
}
Rani Shayto
Rani Shayto
769 Points

Thank you James. Sometimes I forget the basics I recently learnt, and when reading what you had suggested It took me a while to remember if I passed this information in the basics videos or not. Im not sure I did. However, it works! I have a question though, why aren't title and artist written down in this form ("Title, Artist") as a 1 String within quotations?

Thank you

James Attree
James Attree
7,906 Points
James Attree
James Attree
7,906 Points

I believe you're talking about this snippet:

for (title, artist) in song1

'title' and 'artist' are local variables that are created for the scope of the for loop. I could have called them anything at all, they just refer to the 0th and 1st items in the Dictionary ("title" and "song").