数组 函数
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array_sum

(PHP 4 >= 4.0.4, PHP 5)

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。

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

Note:

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）。

参数

array

The input array.

返回值

Returns the sum of values as an integer or float.

更新日志

版本 说明
4.2.1 PHP versions prior to 4.2.1 modified the passed array itself and converted strings to numbers (which most of the time converted them to zero, depending on their value).

范例

Example #2 array_sum() examples

<?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

数组 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 计算数组中所有值的和

用户评论:

igz dot dwd dot 20 at gmail dot com (15-Oct-2011 11:02)

As mysql_fetch_array returns associative and numeric indexes, you can simply use a flag.

<?php
$result = mysql_query("SELECT id, name FROM mytable");
$row = mysql_fetch_array($result, MYSQL_NUM);
array_sum($row);
?>

Hope it helps.

davidcairngorm at gmail dot com (04-Sep-2011 12:37)

If the array is a result from mysql_fetch_array, it contains every value twice and the sum will be double.

pligor at facebook dot com (01-Jun-2011 08:12)

There was a case where I had a complex array, multi-dimesional and non-symmetric (not all elements of a sub-array were arrays themselves)
Although all the leaf elements of this array were numbers. In case you have two variables like that and you wanted to add all the values of the right variable to the left then you would need a function like below.

This is a recursive function which adds the values of two multidimensional arrays with the same key structure:

<?php
function multiDimArrayAdd(& $left, $right)    //created by George Pligor
{
    if(is_array($left) && is_array($right))
    {
        foreach($left as $key => $val)
        {
            if( is_array($val) )
            {
                multiDimArrayAdd($left[$key], $right[$key]);
            }
            $left[$key] += $right[$key];
        }
    }
}
?>

uhehesh at gmail dot com (07-Jan-2011 10:21)

<?php
function avrg()
{
 $count = func_num_args();
 $args = func_get_args();
 return (array_sum($args) / $count);
}
?>

This function calculates average of numbers given as arguments. Examples:
avrg(100, 200, 300) - returns 200.
avrg(5, 6) - returns 5.5.
avrg('foo') - returns 0.

Chris (17-Feb-2010 04:24)

Average array values, ignoring zero values:

<?php
function array_average_nonzero($arr) {
   return array_sum($arr) / count(array_filter($arr));
}
?>

<?php
$arr = array(1,2,3,0,0);
echo array_average_nonzero($arr); // returns 2
echo array_sum($arr) / count($arr); // returns 1.2
?>

hdeus at yahoo dot com (06-Oct-2008 03:01)

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);
   
   
}

?>

c dot heckemueller at befestigungsfuchs dot de (05-Sep-2008 09:30)

<?php
/**
 * sum values in array
 *
 * @param array $arr
 * @param string [optional]$index
 * @return int result
 */
function array_sum_key( $arr, $index = null ){
    if(!is_array( $arr ) || sizeof( $arr ) < 1){
        return 0;
    }
    $ret = 0;
    foreach( $arr as $id => $data ){
        if( isset( $index )  ){
            $ret += (isset( $data[$index] )) ? $data[$index] : 0;
        }else{
            $ret += $data;
        }
    }
    return $ret;
}
?>

With this function you can choose whether you sum specific keys in a multidim array, or a normalized array. it is designed to not trigger errors if a key is not set.

superman1101 (27-Aug-2008 07:29)

To elaborate on djyb2003 at yahoo dot fr. His function can be converted to recursive, but i've made a smaller function to do so:

<?php

 function array_sum_all($array) {
   $func = create_function("&\$arr=0,\$key=0","static \$a=0; if(is_int(\$arr)) { \$a+=\$arr; } return \$a;");
   array_walk_recursive($array,$func);
   return $func();
 }

$tab = array(
                 0 => array ("val1" => 2,"val2" => 5),
                 1 => array ("val1" => 6,"val2" => 10),
                 "toto" => array ("val1" => 15,"val2" => 50)
                );
var_dump(array_sum_all($tab)); //This will output: int(88);
?>

hope this helps someone

djyb2003 at yahoo dot fr (29-Jan-2008 02:31)

here is a function that can sum values like these :

$tab = array(
                 0 => array ("val1" => 2,"val2" => 5)
                 1 => array ("val1" => 6,"val2" => 10)
                 "toto" => array ("val1" => 15,"val2" => 50)
                );

sum_subarrays_by_key( $tab, "val1" );

the function will sum all values with "val1" key in tab subarrays.

function sum_subarrays_by_key( $tab, $key ) {
       
        $sum = 0;
       
        foreach($tab as $sub_array) {
            $sum += $sub_array[$key];
        }
       
        return $sum;
       
    }

it can be transformed to be recursive and do also all depths possible in an array.

Hope it can be usefull!

Coder (17-Aug-2007 12:10)

A much simpler algorithm for array_sub():

<?php
  function array_sub($arr) {
    if (!is_array($arr) || count($arr) == 0) {
      return false;
    } else {
      // get first element
      $base = array_shift($arr);

      return $base - array_sum($arr);
    }
  }
?>

This will return the exact same results that didikdwi's version.

However, didikdwi's result depends on knowing what the first value is. When this likely bug is removed, the code is:

<?php
  function array_sub($arr){
    $temp = array_sum($arr);
    return ( $temp !== false ? -$temp : false );
  }
?>

didikdwi at gmail dot com (18-Jul-2007 02:48)

This is a simple approach to subtract array, both indexed and associative.

  function array_sub($arr) {
    if (!is_array($arr) || count($arr) == 0) {
      return false;
    } else {
      // get first element
      $base = array_shift($arr);

      if (count($arr) == 1) {
        // If only one element, return its
        return $base;
      }

      foreach ($arr as $val) {
        $base -= $val;
      }

      return $base;
    }
  }

// example
$arr1 = array(3, 2, 3);
echo array_sub($arr1);   // Output: -2
$arr2 = array(3.5, 2, 3);
echo array_sub($arr2);   // Output: -1.5
$arr3 = array('a' => 3, 'b' => 2, 'c' => 3);
echo array_sub($arr3);   // Output: -2

herenvardo at gmail dot com (24-Nov-2006 11:28)

I'm not sure if something similar already exists, but I needed it so I made it:
<?php
  /* Performs a pitagoric sum of the elements in $arr
   The pitagoric sum of a set of values is the square root of
   the sum of the sqare power of each value. So, for a, b, c
   it's sqrt(a^2 + b^2 + c^2) */
  /* If any element of $arr is an array itself, the array_sum
   will be used. Alternatively, the values could be used by
   recursion. Returns the integer part (floor) */
  function array_pitag_sum($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;
    }
  }
?>

Tobias Schlemmer (28-Jul-2006 07:41)

<?php
$array1 = array('1'=>'1','2'=>'2','3'=>'3');
$array2 = array(          '2'=>'1','3'=>'2','4'=>'3');
$array3 = array(                  '3'=>'1','4'=>'2','5'=>'3');
$array  = array_sum_values( $array1, $array2, $array3 );
print_r($array);

/**
 * Sums the values of the arrays be there keys (PHP 4, PHP 5)
 * array array_sum_values ( array array1 [, array array2 [, array ...]] )
 */
function array_sum_values() {
    $return = array();
    $intArgs = func_num_args();
    $arrArgs = func_get_args();
    if($intArgs < 1) trigger_error('Warning: Wrong parameter count for array_sum_values()', E_USER_WARNING);
   
    foreach($arrArgs as $arrItem) {
        if(!is_array($arrItem)) trigger_error('Warning: Wrong parameter values for array_sum_values()', E_USER_WARNING);
        foreach($arrItem as $k => $v) {
            $return[$k] += $v;
        }
    }
    return $return;
}
/* result:
Array
(
    [1] => 1
    [2] => 3
    [3] => 6
    [4] => 5
    [5] => 3
)
*/
?>

jodymickey at yahoo dot com (01-Jun-2006 04:23)

In reference to KageKonjou's array_mode function...

If you only want to know the value in the array that occurs most (and not the number of times it actually occured), you can use this short function.  It also suffers from the same problem in that if there is more than one mode, it will return only one.
<?php
    function array_mode($array)
    {
        if(!is_array($array)) return false;
        asort(array_count_values($array));
        return array_pop($array);
    }
?>

Moslehi[atsign]Gmail[dot]com (17-Mar-2006 11:13)

A simple example for numeric values :

<?PHP

function array_average($arr){
$sum = array_sum($arr);
$num = sizeof($arr);
echo $sum/$num;
}

$myarray = array(1,2,3,4);
array_average($myarray); // displays 2.5 as average of 1,2,3,4

?>

[Arash Moslehi]

darianlassan at yahoo dot de (04-Nov-2005 11:57)

function array_avg(&$array)
{
  //**
    returns the average value of all array-values
    or false if no values in array (or not an array)
  **//

  if (!is_array($array) || count($array)==0)
    return false;
  else
    return array_sum($array)/count($array);
} // array_avg()

Please add this function to PHP.

mroach at mroach dot com (27-Sep-2005 09:06)

I ran into a situation where I only wanted to sum elements of an array for certain keys. For that, I wrote this function

<?

function array_sum_by_key()
{
    $args = func_get_args();
   
    $arr = array_shift($args);
           
    $to_sum = is_array($args[0]) ? $args[0] : $args;
   
    $sum = 0;

    foreach ( $arr as $k=>$v ) {
        if ( in_array($k, $to_sum) ) {
            $sum += $v;
        }
    }
   
    return $sum;
}

$arr = array (
    'dog' => 1,
    'cat' => 2,
    'rat' => 4,
    'mat' => 8,
    'bat' => 16
);

echo array_sum_by_key($arr, 'dog', 'mat');

// Result: 9

?>

Alternatively, you can pass the keys to sum as an array

<?

$to_sum = array('dog', 'bat');

echo array_sum_by_key($arr, $to_sum);

// Result: 17

?>

KageKonjou at GMail dot com (12-Aug-2005 05:22)

Not sure where else to put this, but I added something that determines the most commonly occuring item in an array.  Known Bugs: It will always return the first value if no mode are found, and the first mode found if more are found of same or lesser count.

<?php
function array_mode($array) {
 $count = array();
 foreach ($array as $item) {
  $count[$item]++;
 }
 $mostcommon = "";
 $iter = 0;
 foreach ($count as $k => $v) {
  if ($v > $iter) {
   $mostcommon = $k;
   $iter = $v;
  }
 }
 return array("mode" => $mostcommon, "count" => $count[$mostcommon]);
}
?>

punchto at hotmail dot com (16-Mar-2005 03:06)

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;
  }
}

adam at laural dot com dot au (02-Mar-2005 12:37)

Here's a function to return the sum of a portion of an array:

function array_partial_sum($array, $start, $length){
    $new_array = array_slice($array, $start, $length);
    return array_sum($new_array);
}

$array = array(1, 2, 3, 4, 5);
print array_partial_sum($array, 0, 3);  // prints 6

ncheung at maine dot rr dot com (08-Feb-2005 02:02)

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

mucello NOO SPAM @ weatherimages dOt org (22-Oct-2003 11:44)

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);
?>

mcrm at NOTNEEDIT dot freemal dot it (13-Aug-2003 05:40)

Hi people, if someone is searching a function that works also with multimension array, i suggest this :

<?php
function cw_array_count($a) {
  if(!is_array($a)) return $a;
  foreach($a as $key=>$value)
     $totale += cw_array_count($value);
  return $totale;
}

$a[0][E][PS][P][a1]=1;
$a[0][E][PS][P][a2]=2;
$a[0][E][PJ][P][a2]=2;
$a[1][E][PS][E][a3]=3;

echo cw_array_count($a[0]);
// or
echo cw_array_count($a[0][E]);
?>

Bye, Bye.
R.Martina

drverieevil at REMOVEMEasenne dot org (30-Jul-2003 11:14)

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";
?>