CODEWITHSUNDEEP
parse-platformconcatenationswift2
Tilo Delau
Tilo Delau

Reputation: 103

concatenate in swift: Binary operator '+' cannot be applied to operands of type 'String' and 'AnyObject'

I get the error in Swift and don't understand it when I do this:

if(currentUser["employer"] as! Bool == false) { print("employer is false: "+currentUser["employer"] as! Bool) }

But I can do (Its not actually printing anything though, maybe another problem):

if(currentUser["employer"] as! Bool == false) { print(currentUser["employer"]) }

Results in error:

Binary operator '+' cannot be applied to operands of type 'String' and 'AnyObject'

Similarly:

                let currentUser = PFUser.currentUser()!
                let isEmployer = currentUser["employer"]
                print("isEmployer: \(isEmployer)")
                print(currentUser["employer"])

But these two don't work:

                print("employer: "+currentUser["employer"])
                print("employer: \(currentUser["employer"])")

I also happen to be using Parse to get data, and not sure if that is the right way either.

Upvotes: 6

Views: 17077

Answers (1)

vadian
vadian

Reputation: 285072

The error message might be misleading in the first example

if currentUser["employer"] as! Bool == false { 
 print("employer is false: "+currentUser["employer"] as! Bool) 
}

In this case, the error message is supposed to be

binary operator '+' cannot be applied to operands of type 'String' and 'Bool'

because currentUser["employer"] as! Bool is a non-optional Bool and cannot be implicitly cast to String

Those examples

print("employer: "+currentUser["employer"])
print("employer: \(currentUser["employer"])")

don't work because

  • In the first line, currentUser["employer"] without any typecast is an optional AnyObject (aka unspecified) which doesn't know a + operator.
  • In the second line, the string literal "employer" within the String interpolated expression causes a syntax error (which is fixed in Xcode 7.1 beta 2).

Edit:

This syntax is the usual way.

let isEmployer = currentUser["employer"]
print("isEmployer: \(isEmployer)")

Or alternatively, you can write

print("employer is " + String(currentUser["employer"] as! Bool))

Upvotes: 5

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