Swift let keyword
Swift let
keyword is used to define a constant in Swift programming.
A swift constant is immutable. A swift constant once initialized cannot be modified.
In this tutorial, we will learn how to use let
keyword to define a constant in Swift, and its immutable behaviour.
Example
In the following example, we will define a constant in Swift using let
keyword, and print it to the console.
main.swift
let x = 10 print(x)
Output
Now, let us try to modify a constant in Swift. We get an error with the message Cannot assign to value: 'x' is a 'let' constant
, also with a suggestion Change 'let' to 'var' to make it mutable
.
Since, the constant is immutable, we cannot update its value.
Conclusion
In this Swift Tutorial, we learned about let
keyword in Swift, and how to define a constant in Swift using let
keyword.