array_sum

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

array_sum — 计算数组中所有值的和

说明

number array_sum ( array $array )

array_sum() 将数组中的所有值的和以整数或浮点数的结果返回。

参数

array: 输入的数组。

返回值

所有值的和以整数或浮点数的结果返回。

更新日志

版本	说明
4.2.1	PHP 4.2.1 之前的版本修改了传入的数组本身，将其中的字符串值转换成数值（大多数情况下都转换成了零，根据具体值而定）。

范例

Example #1 array_sum() 例子

  <?php
$a  = array( 2 ,  4 ,  6 ,  8 );
echo  "sum(a) = "  .  array_sum ( $a ) .  "\n" ;

 $b  = array( "a"  =>  1.2 ,  "b"  =>  2.3 ,  "c"  =>  3.4 );
echo  "sum(b) = "  .  array_sum ( $b ) .  "\n" ;
 ?>

以上例程会输出：

sum(a) = 20
sum(b) = 6.9

用户评论:

[#1] didatus at dynarize dot de [2014-09-20 21:21:17]

If you want to check if there are for example only strings in an array, you can use a combination of array_sum and array_map like this:

<?php function only_strings_in_array($arr) { return array_sum(array_map('is_string', $arr)) == count($arr); } $arr1 = array('one', 'two', 'three'); $arr2 = array('foo', 'bar', array()); $arr3 = array('foo', array(), 'bar'); $arr4 = array(array(), 'foo', 'bar'); var_dump( only_strings_in_array($arr1), only_strings_in_array($arr2), only_strings_in_array($arr3), only_strings_in_array($arr4) ); ?>

This will give you the following result:
bool(true)
bool(false)
bool(false)
bool(false)

[#2] hdeus at yahoo dot com [2008-10-06 07:01:29]

Here is how you can multiply two arrays in the form of matrixes using a bit of matrix algebra (M*M).
By calling the function multiplyMatrix, you will be multiplying two sparse matrixes (zeros need not be included in the array for the operation to be performed).

<?php $M = array( 0=>array(1=>1,4=>1), 1=>array(2=>1,3=>1), 3=>array(1=>1), 4=>array(5=>1), 5=>array(6=>1) ); $M1 = multiplyMatrix($M, $M); //multiplying $M by itself echo '<pre>';print_r($M1);echo '</pre>'; function multiplyMatrix($M1, $M2) { #Helena F Deus, Oct 06, 2008 ##Multiply two matrixes; $M1 and $M2 can be sparse matrixes, the indexes on both should match if(is_file($M1)) {$matrix1 = unserialize(file_get_contents($M1));} else $matrix1 = $M1; #transpose M2 $M2t = transpose($M2); foreach ($M2t as $row=>$tmp) { ##sum the result of the value in the col multiplied by the value in the vector on the corresponding row foreach ($M1 as $row1=>$tmp1) { $multiply[$row1] = array_rproduct($tmp,$tmp1); if(!$multiply[$row1]){ exit; } } foreach ($multiply as $row1=>$vals) { $sum[$row][$row1]=array_sum($vals); } } $r=transpose($sum); return ($r); } function transpose($M) { foreach ($M as $row=>$cols) { foreach ($cols as $col=>$value) { if($value) $Mt[$col][$row]=$value; } } ksort($Mt); return ($Mt); } function array_rproduct($a1, $a2) { foreach ($a1 as $line=>$cols) { $a3[$line] = $a1[$line]*$a2[$line]; foreach ($a2 as $line2=>$cols2) { $a3[$line2] = $a1[$line2]*$a2[$line2]; } } ksort($a3); return ($a3); } ?>

[#3] herenvardo at gmail dot com [2006-11-24 15:28:24]

I'm not sure if something similar already exists, but I needed it so I made it:
<?php function array_pitag_sum($arr) { if(is_array($arr) { $ret = 0; foreach($arr as $i) { if(is_array($i)) { $s = array_sum($i); $ret += $s*$s; } else { $ret += $i*$i; } } return floor(sqrt($ret)); } else { return $arr; } } ?>

[#4] punchto at hotmail dot com [2005-03-15 19:06:53]

Microsoft Excel - SUMIF()

function sumif($array,$criteria,$sum_array){
  if(is_array($array) && is_array($sum_array) && trim($criteria)!= ""){
    $array_count = (count($array) < count($sum_array)) ? count($array):count($sum_array);
    for($i=0;$i<$array_count;$i++){
      if(ereg("^<",$criteria)){
        $value = ereg_replace("^<","",$criteria);
        $result += $array[$i] < $value ? $sum_array[$i]:0;
      }
      elseif(ereg("^>",$criteria)){
        $value = ereg_replace("^>","",$criteria);
        $result += $array[$i] > $value ? $sum_array[$i]:0;
      }
      else{
        $value = $criteria;
        $result += $array[$i] == $value ? $sum_array[$i]:0;
      }

    }
    return $result ? $result:0;
  }
}

[#5] ncheung at maine dot rr dot com [2005-02-07 18:02:53]

For clarity, array indices containing boolean values such as TRUE and FALSE are added up as though they are 1 and 0 respectively.

[#6] mucello NOO SPAM @ weatherimages dOt org [2003-10-22 15:44:51]

If you want to find the AVERAGE of the values in your array, use the sum and count functions together. For example, let's say your array is $foo and you want the average...

<?php $average_of_foo = array_sum($foo) / count($foo); ?>

[#7] drverieevil at REMOVEMEasenne dot org [2003-07-30 03:14:29]

If some array elements arent integers, function will change them to integers (content of array will not change) type and then sum them.

Example:
<?php $foo[] = "12"; $foo[] = 10; $foo[] = "bar"; $foo[] = "summer"; echo array_sum ($foo); //same as echo "22"; ?>