PHP prepend leading zero before single digit number, on-the-fly
PhpStringNumbersZeroPhp Problem Overview
PHP - Is there a quick, on-the-fly method to test for a single character string, then prepend a leading zero?
Example:
$year = 11;
$month = 4;
$stamp = $year.add_single_zero_if_needed($month); // Imaginary function
echo $stamp; // 1104
Php Solutions
Solution 1 - Php
You can use sprintf: http://php.net/manual/en/function.sprintf.php
<?php
$num = 4;
$num_padded = sprintf("%02d", $num);
echo $num_padded; // returns 04
?>
It will only add the zero if it's less than the required number of characters.
Edit: As pointed out by @FelipeAls:
When working with numbers, you should use %d (rather than %s), especially when there is the potential for negative numbers. If you're only using positive numbers, either option works fine.
For example:
sprintf("%04s", 10); returns 0010
sprintf("%04s", -10); returns 0-10
Where as:
sprintf("%04d", 10); returns 0010
sprintf("%04d", -10); returns -010
Solution 2 - Php
You can use str_pad for adding 0's
str_pad($month, 2, '0', STR_PAD_LEFT);
string str_pad ( string $input , int $pad_length [, string $pad_string = " " [, int $pad_type = STR_PAD_RIGHT ]] )
Solution 3 - Php
The universal tool for string formatting, sprintf:
$stamp = sprintf('%s%02s', $year, $month);