How to solve unexpectedly found nil while Unwrapping an optional value?
99% of the time the above error is caused by a force-unwrapped optional that is nil . You can fix it by avoiding it becomes nil , which is sometimes not possible, so then you use optional binding or optional chaining. Avoid using implicitly unwrapped optionals when you can, unless you have a specific need to use it.
How to fix fatal error unexpectedly found nil while implicitly Unwrapping an optional value?
You also should check that the connections are correct in your storyboard/xib file, otherwise the values will be nil at runtime, and therefore crash when they are implicitly unwrapped. When fixing connections, try deleting the lines of code that define your outlets, then reconnect them.
What should we use for unwrapping value inside optional?
A common way of unwrapping optionals is with if let syntax, which unwraps with a condition. If there was a value inside the optional then you can use it, but if there wasn’t the condition fails. For example: if let unwrapped = name { print(“\(unwrapped.
How do I unwrap optional in Swift?
You can force unwrap an optional by adding an exclamation mark after the optional constant or variable, like this: print(email!) Now, consider the following two scenarios: Instead of having a value, email is nil .
What is guard let in Swift?
Swift gives us an alternative to if let called guard let , which also unwraps optionals if they contain a value, but works slightly differently: guard let is designed to exit the current function, loop, or condition if the check fails, so any values you unwrap using it will stay around after the check.
What problems do optionals solve Swift?
Optionals are Swift’s solution to the problem of representing both a value and the absence of a value. An optional is allowed to hold either a value or nil . Think of an optional as a box: it either contains exactly one value, or is empty. When it doesn’t contain a value, it’s said to contain nil .
What is an implicitly unwrapped optional?
Implicitly unwrapped optionals are a compromise between safety and convenience. Implicitly unwrapped optionals are a compromise between safety and convenience. If you declare a property as optional, then you need to use optional binding or optional chaining every time you access the value of the optional.
What are optional values in Swift?
Swift also introduces optional types, which handle the absence of a value. Optionals say either “there is a value, and it equals x” or “there isn’t a value at all”. Optionals are similar to using nil with pointers in Objective-C, but they work for any type, not just classes.
What is difference between guard and if let in Swift?
With guard let you are creating a new variable that will exist outside the else statement. With if let you aren’t creating any new variable—after the else statement, you only enter the code block if the optional is non-nil.
What is difference between if let and guard let in Swift?
In if let , the defined let variables are available within the scope of that if condition but not in else condition or even below that. In guard let , the defined let variables are not available in the else condition but after that, it’s available throughout till the function ends or anything.
How do I remove optional value in Swift 4?
14 Answers. Actually when you define any variable as a optional then you need to unwrap that optional value. To fix this problem either you have to declare variable as non option or put !( exclamation) mark behind the variable to unwrap the option value.
Why optionals are useful in Swift?
Optionals are in the core of Swift and exist since the first version of Swift. An optional value allows us to write clean code with at the same time taking care of possible nil values. If you’re new to Swift you might need to get used to the syntax of adding a question mark to properties.
When to look for unexpectedly found nil while unwrapping an optional value?
In 99% of cases you’ve force-unwrapped an optional with ! and it was nil, so that’s the first place to look when you run into this error. The most common scenario for the fatal error: Unexpectedly found nil while unwrapping an Optional value error is when you’ve force-unwrapped an optional and it was nil. So far so good.
What is the fatal error of implicit unwrapping?
Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value This crash arises when we attempt to forcefully or Implicitly unwrap an optional and that optional, as the name suggests, does not contain any value.
When to use implicitly unwrapped optionals in SDK?
Implicitly unwrapped optionals are becoming uncommon in SDKs, though. Sometimes you’ve created a struct or a class, and some of its properties are nil before initializing the class, but will never be nil after. In this case, it saves you quite a bit of code (for unwrapping) if you use implicitly unwrapped optionals.
When is an optional value is nil in Swift?
In Swift, an optional can either have an ordinary value, or be nil. When a variable has no value it is nil. Almost every programming language has something similar to nil. It’s undefined in JavaScript, null in Java and NULL in PHP.