I already said that variables have that name because their values can change over time, and that is often useful. However, very often you want to set a value once and never change it, and so we have an alternative to the var
keyword called let
.
The let
keyword creates constants, which are values that can be set once and never again. For example:
let taylor = "swift"
If you try to change that, Xcode will refuse to run your code. It’s a form of safety: when you use constants you can no longer change something by accident.
When you write your own Swift code, you should always use let
unless you specifically want to change a value. In fact, Xcode will warn you if you use var
then don’t change the variable.
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