Get the sum of all digits in a numeric string

Question

How do I find the sum of all the digits in a number in PHP?

score 117 · Answer 1 · answered Jul 12 '10 at 21:47

117

array_sum(str_split($number));

This assumes the number is positive (or, more accurately, that the conversion of $number into a string generates only digits).

answered Jul 12 '10 at 21:47

Artefacto

96,375
17
202
225

Thank you! The simpler, the better! If you don't know whether a number is positive or negative, you could use the abs() function to make it always positive array_sum(str_split(abs($number))); – imelgrat Sep 21 '16 at 15:52
Funny how this got 70+ votes here and on php manual page it gets downvoted by -40 [see here](http://php.net/manual/en/function.array-sum.php#121020) – Manuel Mannhardt Mar 07 '18 at 13:06
It´s not only shorter than any loop, but also faster: PHP has no integer division, so a looping solution has to cast the remaining number from float to int in every iteration. – Titus May 04 '18 at 15:48

NikiC · Answer 2 · 2022-07-12T20:45:28.887

13

Artefactos method is obviously unbeatable, but here an version how one could do it "manually":

$number = 1234567890;
$sum = 0;
do {
    $sum += $number % 10;
}
while ($number = (int) ($number / 10));

This is actually faster than Artefactos method (at least for 1234567890), because it saves two function calls.

edited Jul 12 '22 at 20:45

answered Jul 12 '10 at 22:01

NikiC

100,734
37
191
225

what if $number = "12345678901234567890";? – Shaiful Islam Feb 01 '15 at 19:11
@ShaifulIslam what about it? – Adam May 15 '20 at 10:36
[A duplicate question was asked](https://stackoverflow.com/q/27210718/2943403) because this answer is unexplained. – mickmackusa Aug 08 '22 at 00:43

score 4 · Answer 3 · answered Jul 12 '10 at 21:53

4

Another way, not so fast, not single line simple

<?php

    $n = 123;
    $nstr = $n . "";

    $sum = 0;
    for ($i = 0; $i < strlen($nstr); ++$i)
    {
        $sum += $nstr[$i];
    }
    echo $sum;

?>

It also assumes the number is positive.

answered Jul 12 '10 at 21:53

BrunoLM

97,872
84
296
452

@Frank Farmer Efficiency wouldn't be calculating the string length on each iteration :P – alex Dec 22 '10 at 04:24
True, but that's still probably better than building a whole array via str_split. – Frank Farmer Jan 12 '11 at 02:16

Aries · Answer 4 · 2020-03-09T09:06:22.047

3

function addDigits($num) {

    if ($num % 9 == 0 && $num > 0) {
        return 9;
    } else {
          return $num % 9;
        }
    }

only O(n)

at LeetCode submit result： Runtime: 4 ms, faster than 92.86% of PHP online submissions for Add Digits. Memory Usage: 14.3 MB, less than 100.00% of PHP online submissions for Add Digits.

edited Mar 09 '20 at 09:06

answered Mar 09 '20 at 09:00

Aries

31
2

score 1 · Answer 5 · answered Apr 20 '20 at 23:57

1

<?php 
// PHP program to calculate the sum of digits 
function sum($num) { 
    $sum = 0; 
    for ($i = 0; $i < strlen($num); $i++){ 
        $sum += $num[$i]; 
    } 
    return $sum; 
} 

// Driver Code 
$num = "925"; 
echo sum($num); 
?>

Result will be 9+2+5 = 16

answered Apr 20 '20 at 23:57

user2446600

23
3

Hello! While this code may solve the question, [including an explanation](https://meta.stackexchange.com/q/114762) of how and why this solves the problem would really help to improve the quality of your post, and probably result in more up-votes. Remember that you are answering the question for readers in the future, not just the person asking now. Please [edit] your answer to add explanations and give an indication of what limitations and assumptions apply. – Brian61354270 Apr 21 '20 at 00:39

score 0 · Answer 6 · edited May 30 '15 at 22:38

0

Try the following code:

<?php

$num = 525;
$sum = 0;

while ($num > 0)
{
    $sum= $sum + ($num % 10);
    $num= $num / 10;
}
echo "Summation=" . $sum;

?>

edited May 30 '15 at 22:38

kenorb

155,785
88
678
743

answered May 30 '15 at 19:03

Mayank Dudakiya

3,635
35
35

infinite loop: $num will become a quote after the first digit that is not `0`. Try `while ($num|0)`. And btw: `for(;$num|0;$num/=10)$sum+=$num%10;` – Titus May 04 '18 at 15:45
This answer is missing its educational explanation. – mickmackusa Jul 11 '22 at 21:38

score 0 · Answer 7 · answered Sep 07 '15 at 03:56

0

If interested with regex:

array_sum(preg_split("//", $number));

answered Sep 07 '15 at 03:56

itsazzad

6,868
7
69
89

score 0 · Answer 8 · answered Jul 13 '18 at 20:14

    <?php
echo"----Sum of digit using php----";
echo"<br/ >";
$num=98765;
$sum=0;
$rem=0;
for($i=0;$i<=$num;$i++)
{
$rem=$num%10;
$sum=$sum+$rem;
$num=$num/10;
}
echo "The sum of digit 98765 is ".$sum;
?>
-----------------Output-------------
----Sum of digit using php----
The sum of digit 98765 is 35

score 0 · Answer 9 · edited Aug 19 '18 at 19:51

0

// math before code 

// base of digit sums is 9 

// the product of all numbers multiplied by 9 equals 9 as digit sum

$nr = 58821.5712; // any number

// Initiallization 

$d = array();

$d = explode(".",$nr); // cut decimal digits

$fl = strlen($d[1]); // count decimal digits

$pow = pow(10 ,$fl); // power up for integer

$nr = $nr * $pow; // make float become integer

// The Code

$ds = $nr % 9; // modulo of 9 

if($ds == 0) $ds=9; // cancel out zeros

echo $ds;

edited Aug 19 '18 at 19:51

scopchanov

7,966
10
40
68

answered Aug 19 '18 at 14:42

stereoIII6

11
2

maximum 7 float digits – stereoIII6 Aug 19 '18 at 14:55

score -1 · Answer 10 · answered Jan 05 '18 at 07:29

Assume you want to find the sum of the digits of a number say 2395 the simplest solution would be to first split the digits and find out the sum then concatenate all the numbers into one single number.

<?php
    $number=2;
    $number1=3;
    $number2=9;
    $number3=5;
    $combine=$number.$number1.$number2.$number3;
    $sum=$number+$number1+$number2+$number3;
    echo "The sum of $combine is $sum";
     ?>

score -1 · Answer 11 · edited Dec 21 '19 at 13:18

-1

One way of getting sum of digit however this is a slowest route.

$n=123;
while(($n=$n-9)>9);
echo "n: $n";

edited Dec 21 '19 at 13:18

cfnerd

3,658
12
32
44

answered Dec 21 '19 at 11:30

manimaran vadivel

31
5

score -2 · Answer 12 · answered May 07 '13 at 16:19

-2

<html>
<head>
<title>detail</title>
</head>
<body>
<?php
$n = 123;
$sum=0; $n1=0;

  for ($i =0; $i<=strlen($n);$i++)
 {

  $n1=$n%10;

   $sum += $n1;
   $n=$n/10;
  }
 echo $sum;

 ?>
 </body>
</html>

answered May 07 '13 at 16:19

user2359154

1

score -2 · Answer 13 · edited Feb 27 '14 at 04:12

Here's the code.. Please try this

   <?php 
    $d=0;
   $num=12345;

   $temp=$num;

   $sum=0;

   while($temp>1)

     {
      $temp=$temp/10;

        $d++;
         }

     echo "Digits Are : $d </br>";

      for (;$num>1;)

             {
              $d=$num%10;

             $num=$num/10;

             $sum=$sum+$d;

             }

           echo "Sum of Digits is : $sum";

   ?>

Get the sum of all digits in a numeric string

13 Answers13

Linked

Related