unwrapping multiple optionals in if statement

Question

I want to unwrap two optionals in one if statement, but the compiler complaints about an expected expression after operator at the password constant. What could be the reaso

Answer 1

Swift 4

if let suggestions = suggestions, let suggestions1 = suggestions1 {

        XCTAssert((suggestions.count > suggestions1.count), "TEST CASE FAILED: suggestion is nil. delete sucessful");
}

Answer 2

The usage

if let x = y {
}

is not equivalent to

if (let x = y) { // this is actually not allowed
}

"if let" is effectively a two-word keyword, which is equivalent to

if y != nil {
    let x = y!
    // rest of if let block
}

Answer 3

How about wrapping the optionals in a tuple and using switch to pattern match?

switch (self.emailField?.text, self.passwordField?.text) {
case let (.Some(email), .Some(password)):
    // unwrapped 'email' and 'password' strings available here
default:
    break
}

It's definitely a bit noisier, but at least it could also be combined with a where clause as well.

Answer 4

Update for Swift 3:

if let email = emailField?.text, let password = passwordField?.text {
}

each variable must now be preceded by a let keyword

Answer 5

Before Swift 1.2

Like @James, I've also created an unwrap function, but this one uses the existing if let for control flow, instead of using a closure:

func unwrap<T1, T2>(optional1: T1?, optional2: T2?) -> (T1, T2)? {
  switch (optional1, optional2) {
  case let (.Some(value1), .Some(value2)):
    return (value1, value2)
  default:
    return nil
  }
}

This can be used like so:

if let (email, password) = unwrap(self.emailField?.text, self.passwordField?.text)
{
  // do something
}

From: https://gist.github.com/tomlokhorst/f9a826bf24d16cb5f6a3

Note that if you want to handle more cases (like when one of the two fields is nil), you're better off with a switch statement.

Answer 6

I can't explain why the above code doesn't work, but this would be good a replacement:

if let email = self.emailField?.text 
{
    if let password = self.passwordField?.text 
    {
        //do smthg
    }
}