Функция PHP vfprintf

int vfprintf ( resource handle, string format, array args )

Write a string produced according to format to the stream resource specified by handle. format is described in the documentation for sprintf.

Operates as fprintf but accepts an array of arguments, rather than a variable number of arguments.

Returns the length of the outputted string.

vfprintf: zero-padded integers

<?php
   if (!($fp = fopen('date.txt', 'w')))
      return;

   vfprintf($fp, "%04d-%02d-%02d", array($year, $month, $day));
   // will write the formatted ISO date to date.txt
?>

See also: printf, sprintf, sscanf, fscanf, vsprintf, and number_format.