Swift:Missing Argument Label 'Xxx' in Call

Swift : missing argument label 'xxx' in call

One possible reason is that it is actually a method. Methods are very sneaky, they look just like regular functions, but they don't act the same way, let's look at this:

func funFunction(someArg: Int, someOtherArg: Int) {
    println("funFunction: \(someArg) : \(someOtherArg)")
}

// No external parameter
funFunction(1, 4)

func externalParamFunction(externalOne internalOne: Int, externalTwo internalTwo: Int) {
    println("externalParamFunction: \(internalOne) : \(internalTwo)")
}

// Requires external parameters
externalParamFunction(externalOne: 1, externalTwo: 4)

func externalInternalShared(#paramOne: Int, #paramTwo: Int) {
    println("externalInternalShared: \(paramOne) : \(paramTwo)")
}

// The '#' basically says, you want your internal and external names to be the same

// Note that there's been an update in Swift 2 and the above function would have to be written as:

func externalInternalShared(paramOne paramOne: Int, #paramTwo: Int) {
    print("externalInternalShared: \(paramOne) : \(paramTwo)")
}

externalInternalShared(paramOne: 1, paramTwo: 4)

Now here's the fun part, declare a function inside of a class and it's no longer a function ... it's a method

class SomeClass {
    func someClassFunctionWithParamOne(paramOne: Int, paramTwo: Int) {
        println("someClassFunction: \(paramOne) : \(paramTwo)")
    }
}

var someInstance = SomeClass()
someInstance.someClassFunctionWithParamOne(1, paramTwo: 4)

This is part of the design of behavior for methods

Apple Docs:

Specifically, Swift gives the first parameter name in a method a local parameter name by default, and gives the second and subsequent parameter names both local and external parameter names by default. This convention matches the typical naming and calling convention you will be familiar with from writing Objective-C methods, and makes for expressive method calls without the need to qualify your parameter names.

Notice the autocomplete:

Swift error: missing argument label 'name:' in call

Swift functions can specify local and external argument names:

func greet(who name: String = "world") {
    println("hello \(name)")
}

// prints "hello world"
greet()

// prints "hello jiaaro"
greet(who:"jiaaro")

// error
greet("jiaaro")

// error
greet(name: "jiaaro")

To opt out of this behavior you can use an underscore for the external name. Note that the first parameter implicitly uses the "no external name" behavior:

func greet(name: String = "world", _ hello: String = "hello") {
    println("\(hello) \(name)")
}

// prints "hello world"
greet()

// prints "hello jiaaro"
greet("jiaaro")

// prints "hi jiaaro"
greet("jiaaro", "hi")

// error
greet(name: "jiaaro")

The following is now disallowed in Swift 2.0, see below for equivalent code.

You can use the # prefix to use the same local and external name for the first parameter:

func greet(#name: String = "world", hello: String = "hello") {
    println("\(hello) \(name)")
}

// prints "hi jiaaro"
greet(name: "jiaaro", hello: "hi")

Swift 2.0 code:

func greet(name name: String = "world", hello: String = "hello") {
    println("\(hello) \(name)")
}

// prints "hi jiaaro"
greet(name: "jiaaro", hello: "hi")

Swift Contains Array Error: Missing argument label 'where:' in call

The error is a bit misleading. array(forKey returns [Any]? so you have to cast the object to the expected type to ensure that the type conforms to Equatable

if let items = UserDefaults.standard.array(forKey: "purchasedItems") as? [Int] {
    if items.contains(1) {
       print("works!")
    }
}

Converting swift 1.2 code to swift 2: Missing argument label in call

Change:

let base64EncodedString = utf8str?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(0))

to:

let base64EncodedString = utf8str?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))

Swift and Firebase Database - Missing argument label 'andPriority' in call

There is a missing ) after the block

self.ref.child("users").child(user?.user.uid).setValue(newUserInfo, withCompletionBlock: { (error, ref) in
  print("New User Saved")
}

Add ) at the end, like this

self.ref.child("users").child(user?.user.uid).setValue: newUserInfo, withCompletionBlock: { (error, ref) in
  print("New User Saved")
})

Hope it helps

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