optionalbinding.swift

//OPTIONAL BINDING
let weatherDictionary: [String: String] = ["currentWeather" : "22.4", "weeklyWeather" : "25.9"]
if let weekly = weatherDictionary["weeklyWeather"] {
    print(weekly)
}
//prints 25.9

//DOWNSIDES OF USING IF LET AND WHY GUARD SOLVE THIS
struct Friend {
    let name : String
    let age: String
    let address: String?
}

//PROBLEM: here we are returning nil checking for all the data and sometimes we need to check just for one var and pass the others
func new(friendDict: [String: String]) -> Friend? {
    
    if let name = friendDict["name"], let age = friendDict["age"] {
        let address = friendDict["address"]
        return Friend(name: name, age: age, address: address)
    } else {
        return nil
    }
}

//ALTERNATIVE SOLUTION USING EARLY EXIT USING GUARD.
func newFriend(friendDict: [String: String]) -> Friend? {
    guard let name = friendDict["name"], let age = friendDict["age"] else {
        return nil
    }
    let address = friendDict["address"]
    return Friend(name: name, age: age, address: address)
}