Component separated by string crashing app swift - ios

Question

I have an app that converts textField input into an array of Int's by using componentSeparatedByString(",") but when i enter more than one comma in the textfield the app crashes, been trying to find a solution online but no luck, how can i fix this? I can keep it from crashing by checking for characters.first == "," ||characters.last == ",", but not consecutive commas.
enterValueLabel.text = ""
let circuits = circuitNumbersTextField.text!.componentsSeparatedByString(",")
let circuitNumbers = circuits.map { Int($0)!}
CircuitColors(circuitNumber: circuitNumbers, phaseColors: circuitPhaseColors )
if /*circuitNumbersTextField.text!.characters.first != "," || */circuitNumbersTextField.text!.characters.last != "," || (circuitNumbersTextField.text!.characters.first != "," && circuitNumbersTextField.text!.characters.last != ",")

Answer 1

Here's what I would do to make your code work. What is important here is the general idea, not the specific example I'm using (although it should work for you).
First, let's safely unwrap the text label:
if let text = circuitNumbersTextField.text {
}
Now that we avoid using circuitNumbersTextField.text! we know that an error wouldn't come from there.
Then we cut the sentence in components:
if let text = circuitNumbersTextField.text {
let circuits = text.componentsSeparatedByString(",")
}
We use flatMap to safely unwrap the Optionals returned by Int():
if let text = circuitNumbersTextField.text {
let circuits = text.componentsSeparatedByString(",")
let circuitNumbers = circuits.flatMap { Int($0) }
// circuitNumbers will only contain the successfully unwrapped values
}
Your code snippet:
if let text = circuitNumbersTextField.text {
let circuits = text.componentsSeparatedByString(",")
let circuitNumbers = circuits.flatMap { Int($0) }
if (circuits.first != "," && circuits.last != ",") || circuits.first != "," || circuits.last != "," {
// condition is met
} else {
// condition is not met
}
}
You can now safely use circuitNumbers in this code block without crashing.