Swift lets you create both variables and constants as ways to reference your data, but there's a strong push (even Xcode warnings!) if you create things as variables then never change them. To make a constant, use
let like this:
let x = 10
To make a variable, use
var like this:
var y = 20
The reason Swift strongly encourages you to use constants wherever possible is because it's safer: if you say "this value will never change," then Swift will refuse to let you change it even by accident. It also opens the possibility of compiler optimizations if the system knows certain data will not change.
Available from iOS 7 – see Hacking with Swift tutorial 1
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Build for watchOS
Take your existing Swift skills to Apple's tiniest platform – check out Hacking with watchOS!