CODEWITHSUNDEEP
arraysswiftstringclosures
richc
richc

Reputation: 1678

Cannot convert value of type 'String' to expected argument type '(Any) throws -> Bool'

I am struggling with the syntax for checking an array to see if it contains a string. I am checking a string array using contains function. But get an error noted, and I can't work out the syntax for the closure. Can anyone help?

var connectedPeripherals = [String]()

if let connectedPeripherals = UserDefaults.standard.array(forKey: "ConnectedPeripherals") {
    if connectedPeripherals.contains(where: (peripheral.identifier.uuidString)) {
     // Gives error: "Cannot convert value of type 'String' to expected argument type '(Any) throws -> Bool'"
     manager.connect(peripheral, options: nil)
    }
}

Upvotes: 0

Views: 4863

Answers (2)

OOPer
OOPer

Reputation: 47876

Two things:

  • The return type of array(forKey:) is [Any]?, its Element type Any is useless for almost all operations. You should better cast it to an appropriate type when you know the actual Element type.

  • The method name contains has many overloads, you may want to call contains(_:), not contains(where:).

Try this:

if let connectedPeripherals = UserDefaults.standard.array(forKey: "ConnectedPeripherals") as? [String] {
    if connectedPeripherals.contains(peripheral.identifier.uuidString) {
        manager.connect(peripheral, options: nil)
    }
}

Or, as suggested by Leo Dabus, this may be better:

if let connectedPeripherals = UserDefaults.standard.stringArray(forKey: "ConnectedPeripherals") {
    if connectedPeripherals.contains(peripheral.identifier.uuidString) {
        manager.connect(peripheral, options: nil)
    }
}

Upvotes: 2

Otávio
Otávio

Reputation: 733

The function contains(where:) expects a closure as parameter, you are passing a String.

So to fix your code it should be:

var connectedPeripherals = [String]()

if let connectedPeripherals = UserDefaults.standard.array(forKey: "ConnectedPeripherals") as? String {
    if connectedPeripherals.contains(where: { $0 == peripheral.identifier.uuidString }) {
        manager.connect(peripheral, options: nil)
    }
}

Upvotes: 3

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