/* EXAMPLE

print_r(add_leading_zeros(range(1,100)));

*/

function add_leading_zeros($array) {
	
	foreach($array as $key=>$value) $array[$key] = str_pad($value,strlen(max($array)),'0',STR_PAD_LEFT);
	
	return $array;
}

/* EXAMPLE

print_r(addleadingzeros(range(1,100)));

*/

function addleadingzeros($array) {
	
	foreach($array as $key=>$value) $array[$key] = str_pad($value,strlen(max($array)),'0',STR_PAD_LEFT);
	
	return $array;
}

/* EXAMPLE

print_r(addleadingzeros(range(1,100)));

*/

function addleadingzeros($array) {
	
foreach($array as $key=>$value) $array[$key] = str_pad($value,strlen(max($array)),'0',STR_PAD_LEFT);
	
return $array;
}

This PHP code snippet checks each integer in an array. If necessary, one or more leading zeros are added to an integer. Note that each integer becomes a string.

add leading zeros

list, array

PHP