I want to reach the input of a function.

I am sorry about the layout. I made it flat but it came out this way.

Burak Boysan

Function parameters can't be referenced outside of the scope of the function because they don't exist. What you can do is create a variable called name and store the name you are going to pass in, like so:

var name = "Alex"
if let culprit = moneyBorrowed(name: name) {}

Your code can also be simplified a bit, here's the final product I have:

func moneyBorrowed(#name: String) -> String? {
    for (key,value) in ["Alex": "1000","David": "30"] {
        if key == name {
            return value
        }
    }
    return nil
}

var name = "Alex"

if let culprit = moneyBorrowed(name: name) {
    println("\(name) borrowed \(culprit)£")
}

Couple things, you don't need to store the dictionary in a constant, i.e. Borcular, to be able to iterate over it in a for loop. The loop can access the dictionary directly.

Second, you can use a tuple to store the dictionary key and value directly so that inside your for loop you can just reference the keys and values without having to use dot notation. This also makes it more readable since you know its a dictionary key versus isim.0

Third, in the function you've defined name as an external parameter. External names don't mean that you can use that variable outside of the function scope, it's mostly intended for readability so that when using the function you get a clean human readable name, whereas inside the body, you can use something shorter for brevity. A good example given in the Swift docs:

func join(string s1: String, toString s2: String, withJoiner joiner: String)
    -> String {
        return s1 + joiner + s2
}

In this example when using the function, we see the param names listed as string, toString and withJoiner but the implementation of the function uses s1, s2 and joiner.

Finally, to use variables within a string like in your println statement, you need to use string interpolation. The variable/constant needs to be inside a set of empty parentheses with a preceding backslash, like so:

println("\(name) borrowed \(culprit)£")

Hope this helps!