Formatting a number with leading zeros in PHP [duplicate]

Answer 1

When I need 01 instead of 1, the following worked for me:

$number = 1;
$number = str_pad($number, 2, '0', STR_PAD_LEFT);

Answer 2

Use sprintf :

sprintf('%08d', 1234567);

Alternatively you can also use str_pad:

str_pad($value, 8, '0', STR_PAD_LEFT);

Answer 3

$no_of_digit = 10;
$number = 123;

$length = strlen((string)$number);
for($i = $length;$i<$no_of_digit;$i++)
{
    $number = '0'.$number;
}

echo $number; ///////  result 0000000123

Answer 4

Simple answer

$p = 1234567;
$p = sprintf("%08d",$p);

I'm not sure how to interpret the comment saying "It will never be more than 8 digits" and if it's referring to the input or the output. If it refers to the output you would have to have an additional substr() call to clip the string.

To clip the first 8 digits

$p = substr(sprintf('%08d', $p),0,8);

To clip the last 8 digits

$p = substr(sprintf('%08d', $p),-8,8);

Answer 5

Given that the value is in $value:

• To echo it:

  printf("%08d", $value);

• To get it:

  $formatted_value = sprintf("%08d", $value);

That should do the trick

Answer 6

If the input numbers have always 7 or 8 digits, you can also use

$str = ($input < 10000000) ? 0 . $input : $input;

I ran some tests and get that this would be up to double as fast as str_pad or sprintf.
If the input can have any length, then you could also use

$str = substr('00000000' . $input, -8);

This is not as fast as the other one, but should also be a little bit faster than str_pad and sprintf.

Btw: My test also said that sprintf is a little faster than str_pad. I made all tests with PHP 5.6.

Edit: Altough the substr version seems to be still very fast (PHP 7.2), it also is broken in case your input can be longer than the length you want to pad to. E.g. you want to pad to 3 digits and your input has 4 than substr('0000' . '1234', -3) = '234' will only result in the last 3 digits