Print 0001 to 1000 in Kotlin. How to add padding to numbers?

Question

I want to print 0001 (note the 3 preceding 0s), and incremental 1 at a time, and reach 1000 to stop. How could I do that in Kotlin without complex appending the 0s myself?

The below is not helping as it will not have preceding 0s.

for (i in 1..1000) print(i) 

Answer 1

You can use padStart:

(0..1000)     .map { it.toString().padStart(4, '0') }     .forEach(::println) 

It’s part of the Kotlin Standard Library and available for all platforms.

Answer 2

If you are satisfied with a JVM-specific approach, you can do what you'd to in Java:

(1..1000).forEach { println("%04d".format(it)) } 

String.format is an extension function defined in StringsJVM and it delegates straight to the underlying String.format, so it's not in the universal standard library.