Cannot find variable in scope

Question

in Swift I need to use a variable which I created in a if/else outside of it. I made a little code just for showing the problem

let test = 0
if test == 0 {
    let a = "Test is 0"
} else {
    let a = "Test is not 0"
}

print(a)

the result is cannot find a in scope

I need the value of the variable outside of the if statement without creating the variable outside first. How I can do that please?

Joakim Danielson · Accepted Answer · 2020-11-18 21:15:18Z

5

You can create the variable outside, even if it is a let variable as long it is assigned a value both in the if and else clause so it always gets set.

let test = 0
let a: String
if test == 0 {
    a = "Test is 0"
} else {
    a = "Test is not 0"
}

answered Nov 18, 2020 at 21:15

Joakim Danielson

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4 Comments

Sanzio Angeli Over a year ago

I did not know this... very interesting and helpful. Surprised I don't see this used more often in tutorials and code samples. Is it not advised?

Joakim Danielson Over a year ago

Not sure why it is not used more because it is a very useful tool and also if you make a mistake, say forget the else in this case, the compiler will generate an error so it's perfectly safe.

Georg Weber Over a year ago

This I know. But like I sad in the description, I would like to resolve this without declare the variable outside

Joakim Danielson Over a year ago

@GeorgWeber I think you need to learn the basics about variable declaration, you can never use a variable outside of the scope that it was declared in. A variable declared in a function can only be used in that function, a variable declared within an if clause can only be used inside that clause and so on. So what you are asking is impossible.

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