Get the sum of digits in PHP

Question

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

Solution 1

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).

Solution 2

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.

Solution 3

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.

Solution 4

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.

Solution 5

<?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

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