How to format a number with padding in Erlang

Question

I need to pad the output of an integer to a given length.

For example, with a length of 4 digits, the output of the integer 4 is \"0004\" instead of \"4\". How can I

Answer 1

adding a bit of explanation to Zed's answer:

Erlang Format specification is: ~F.P.PadModC.

"~4..0B~n" translates to:

 ~F. = ~4.  (Field width of 4)
  P. =   .  (no Precision specified)
Pad  =  0   (Pad with zeroes)
Mod  =      (no control sequence Modifier specified)
  C  =  B   (Control sequence B = integer in default base 10)

and ~n is new line.