在php中添加两个数字并保留前导零

Question

I need to add numbers in php without changing the number format like below

$a = "001";  
$b = "5";  
$c = $a+$b;  

Now the result comes like "6" but I need "006" if $a is "01" then the result should be "06".

Thanks

Answer 1

Technically speaking, the $a and $b in your example are strings - when you use the addition operator on them they converted to integers which can't retain leading zeroes. More details on string-to-number conversion are in the manual

Something like this would do it (assuming positive integer strings with leading zeros)

#figure out how long the result should be
$len=max(strlen($a), strlen($b));

#pad the sum to match that length
$c=str_pad($a+$b, $len, '0', STR_PAD_LEFT);

If you always know how long the string has to be, you could use sprintf , eg

$c=sprintf('%03d', $a+$b);

Here, % introduces a placeholder, 03 tells it we want zero padded to fill at least 3 digits, and d tells it we're formatting an integer.

Answer 2

Hope this would help you:

<?php
$a="001";
$b="5";
$l=max(strlen($a),strlen($b));
$c=str_pad($a+$b, $l,"0", STR_PAD_LEFT);
echo $c;
?>

Answer 3

For common case. Your code should looks like this.

$a = someFormat($original_a);
$b = someFormat2($original_b); // $b has different format.
$c = someFormat($a + $b);

Or, you need write formatRecognition function.

$a = getValueA();
$b = getValueB();
$c = someFormat(formatRecognition($a), $a + $b);