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iOS Swift Functions and Optionals Optionals Exercise: isDivisible function

Jonathan Fernandes
Jonathan Fernandes
Courses Plus Student 22,784 Points

use of if-let

Here is my code:

func isDivisible (#dividend:Int, #divisor: Int) -> Bool? {

if dividend % divisor == 0 {
    return true

return nil


if isDivisible(dividend: 4, divisor: 2) == true { println("Divisible")}

else {println("Not Divisible")}

this works to solve the problem... in the answer portion of the video, they used the following code to call the function:

if let culprit = isDivisible(dividend: 4, divisor: 2) { println("Divisible") } else { println("Not Divisible") }

I was confused because I could not figure out the significance of the "if let" keyword. if you take out let, i get an error. Does if let basically mean that as long as this is not nil, execute the code that follows?

1 Answer

Sebastien Thomas
Sebastien Thomas
16,502 Points

Hi Jonathan,

That's exactly right. Using the if let syntax is a good habit to take as it is less error-prone because if there is no value returned for some reason, the code in brackets does not execute.