How to format numbers similar to Stack Overflow reputation format

Question

I want to convert a number into a string representation with a format similar to Stack Overflow reputation display.

e.g.

• 999 == \'999\'
• 1000 =

Answer 1

divide by 1000 then if result is greater than 1 round the number and concantenate a "k" on the end.

If the result is less than 1 just output the actual result!