confused with 'return' in Swift

Question

hi all,

i am confused with 'return' in swift. I understand if it is used to return the value in a function, if it is used something like this i understand

func double (value: int) -> Int {
return value * 2
}

but I often see just 'return' is used , i mean something like in guard statement in optional binding like this

guard let value = value else (
print ("nothing")
return
}

so what the purpose of just 'return' in the guard statement like this ? actually i often see not only in guard statement of optional binding. i always find this problem when writing code, when i want to use optional string from a dictionary

let info = ["name":"sarah","hometown":"sydney"]

class UserInfo {



    func getTheName () -> String {
        guard let name = info["name"] else {return}

         return name
    }



}

xcode error :  non-void function should return a value (even though i have written 'return name')

even though i have written 'return name', but xcode still consider that i have not returned a value. is it because of 'return' in guard statement ?

so could you please tell me the purpose of 'return' in swift ? it is confusing for me

Thanks in Advance :)

Answer 1 · 2017-09-26T01:23:06Z

September 26, 2017 1:23am

In the situation of the name not being present you would want to throw an error and then handle the error. The function is expected to return a String but if name is not present it will not.

You could always do this to satisfy it:

    func getTheName () throws -> String {
        guard let name = info["name"] else {return "No name"}

        return name
    }

Yes you are right you are returning a value but you can also return nothing and just break out of the function.

Place this into a playground:

var sum = 0

func method(){
    let num = 0
    if num == 1 {
        print("Equal")
    } else {
        print("Not Equal")
        return //stops further execution of method
    }
    //The 2 lines of code below will not be executed since num is not equal to 1
    sum = sum + num
    print(sum)
}

method()

Now change the value of num to 1 and watch it finish executing.

Or as you stated you can return a value as well:

func someNumber() -> Int {
    return 1 + 2
}

let value = someNumber()
print(value)

Also here is how you can format your code for the forum.

```Swift
    ///Code goes here
``` /// and then 3 more back ticks below the code

Answer 2 · 2017-09-26T01:58:43Z

September 26, 2017 1:58am

Thanks Brandon...

Welcome to the Treehouse Community

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anna saraswati

anna saraswati

confused with 'return' in Swift

2 Answers

Brandon Mahoney

Brandon Mahoney

Brandon Mahoney

Brandon Mahoney

anna saraswati

anna saraswati