Local and Global Variables

Local variables are defined within a function, method, or closure:

func printSomething() {
    let localString = "I'm local!"
    print(localString)
}

func printSomethingAgain() {
    print(localString) // error
}

Global variables are defined outside of a function, method, or closure, and are not defined within a type (think outside of all brackets). They can be used anywhere:

let globalString = "I'm global!"
print(globalString)

func useGlobalString() {
    print(globalString) // works!
}

for i in 0..<2 {
    print(globalString) // works!
}

class GlobalStringUser {
    var computeGlobalString {
        return globalString // works!
    }
}

Global variables are defined lazily (see “Lazy Properties” example).

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