PHP number format 4 digits [duplicate]

Question

For example, I have this format: $s_number = "12"; And for this input, I need 0012 as the output:

Another example:

Input $s_number = "3"; Output: 0003

Every time I need 4 digits I would like this to happen.

Answer 1

It won't be a number (but a string), but you can do that using str_pad. In your examples:

$s_number = str_pad( "12", 4, "0", STR_PAD_LEFT );
$s_number = str_pad( "3", 4, "0", STR_PAD_LEFT );

Answer 2

Use str_pad() for that:

echo str_pad($number, 4, '0', STR_PAD_LEFT);