Swift number formatting

Question

I am just starting to get to know Swift but I am having a serious problem with number formatting at an extremely basic level.

For example, I need to display an integer w

Answer 1

You can construct a string with a c-like formatting using this constructor:

String(format: String, arguments:[CVarArgType])

Sample usage:

var x = 10

println(String(format: "%04d", arguments: [x])) // This will print "0010"

If you're going to use it a lot, and want a more compact form, you can implement an extension like this:

extension String {
    func format(arguments: [CVarArgType]) -> String {
        return String(format: self, arguments: arguments)
    }
}

allowing to simplify its usage as in this example:

"%d apples cost $%03.2f".format([4, 4 * 0.33])