Unwrap String and check emptiness in the same if statement

Question

I want to achieve this

if let large = imageLinks.large {

    if !large.isEmpty {

        result = large
    }
}

in a single if statement, something like this (this does not compiles)

if let large = imageLinks.large where !large.isEmpty {

    result = large       
}

Is it possible?

Your code should work in my opinion. What's the error you got? — Christian, Mar 20 '15 at 11:37
Possible duplicate of [Check string for nil & empty](https://stackoverflow.com/questions/29381994/check-string-for-nil-empty) — Suragch, Jun 20 '18 at 12:35

score 6 · Accepted Answer · answered Mar 20 '15 at 11:34

It 's not yet possible. With the actual Version of swift the if let statement is pretty poor.

But with Swift 1.2 (it will be available in Xcode 6.3). You will be able to do this:

(SWIFT 1.2)

if let large = imageLinks.large where !large.isEmpty {

    result = large       
}

But now you cannot. You can do something like:

if  imageLinks.large != nil && !imageLinks.large!.isEmpty {
   result = large!;
}

Note: Swift use "Lazy Evaluation" If the first part imageLinks.large != nil is false it will not Evaluate the second part, so it will not crash.

But I don't found this solution beautiful (too much force unwrapping).

score 6 · Answer 2 · edited Oct 22 '19 at 17:30

6

In swift 4.4, generics to the rescue \o/

public extension Optional where Wrapped == String {
    var isEmptyOrNil: Bool { (self ?? "").isEmpty }
}

usage

if nameField.text.isEmptyOrNil {
    //doSomething...
}

edited Oct 22 '19 at 17:30

Jakub Truhlář

answered Jul 19 '18 at 14:28

sachadso

score 1 · Answer 3 · answered Mar 20 '15 at 13:35

1

In Swift 1.1

If you don't like force unwrapping, you can:

if let large = imageLinks.large?.isEmpty == false ? imageLinks.large : nil {
    result = large
}

It's not so beautiful anyway :(

answered Mar 20 '15 at 13:35

rintaro

3 Answers3