Is there a built-in Swift function to pad Strings at the beginning?

Question

The String function padding(toLength:withPad:startingAt:) will pad strings by adding padding characters on the end to "fill out" the string to the desired length.

Is there an equivalent function that will pad strings by prepending padding characters at the beginning?

This would be useful if you want to right-justify a substring in a monospaced output string, for example.

I could certainly write one, but I would expect there to be a built-in function, seeing as how there is already a function that pads at the end.

Answer 1

You can do this by reversing the string, padding at the end, end then reversing again…

let string = "abc"

// Pad at end
string.padding(toLength: 7, withPad: "X", startingAt: 0)
// "abcXXXX"    

// Pad at start
String(String(string.reversed()).padding(toLength: 7, withPad: "X", startingAt: 0).reversed())
// "XXXXabc"