Swift – guard

Swift Document

How to use guard?

Swift documentation (link) explain details

If let and guard

This is an example of guard

// guard
var str : String? = nil


if let st = str {
    print(st)
}
// Cannot use st

func guard2() {
    let str2 : String? = nil
    guard let st2 = str2 else {
        return
    }
    // Can use after guard
    print(st2)
}

func guard2X() {
    let str2 : String? = "stq"
    guard let st2 = str2 else {
        return
    }
    // Can use st2 after guard
    print(st2)
}

if let cannot use variable after block.

if guard does not meet use following stop execution basically

• return
• break
• continue
• throw