Question

我有一个数组，我从数据库

获取

*

Array
(
    [0] => Array
        (
            [year] => "2016"
            [numb] => 1
        )
    [1] => Array
        (
            [year] => "2016"
            [numb] => 3
        )
    [2] => Array
        (
            [year] => "2017"
            [numb] => 3
        )
    [3] => Array
        (
            [year] => "2016"
            [numb] => 1
        )
    [4] => Array
        (
            [year] => "2018"
            [numb] => 2
        )
)

*

我想结果数组将是这样的

Array
(
    [2016] => 5
    [2017] => 8
    [2018] => 10
)

这意味着：2016 = 1 + 3 + 1 = 5,2017 =（year2016）+ 3,2018 =（year2016）+（year2017）+2。但2016年并不总是第一年，这取决于数据库

Answer 1

第一种方法：使用数据库查询（更好的推荐方式）

SELECT DISTINCT y1.year,
(SELECT sum(y2.numb) FROM nums y2 WHERE y2.year <= y1.year) AS numb_total
FROM nums y1

小提琴：http://sqlfiddle.com/#!9/0c6ec5/12

第二种方法：使用PHP方法

// create a container for the new array
$newArray = [];

// get the unique years from array
$years = array_unique(array_column($array, "year"));

// loop them
foreach($years as $year){

    // filter the array to match the years less or equal of the current year
    $year_filtered = array_filter($array, function($d)use($year){ return intval($d["year"]) <= intval($year);});

    // sum the numbers
    $total = array_sum(array_column($year_filtered, "numb"));

    // place the values in the new array
    $newArray[$year] = $total;
}

// echo the output (for debugging purposes)
print_r($newArray);

小提琴：https://3v4l.org/UK9A8

Answer 2

$MyNewArray = array();
foreach($YourArray as $Row){
    $MyNewArray[$Row->year] = $MyNewArray[$Row->year]+$Row->numb;
}
print_r($MyNewArray);

Answer 3

我创建了一个新的数组，其中键作为年份，值为麻木然后按键（年份）对数组进行排序然后我将值汇总到另一个循环中。

可能有一种更简单的方法，但这是我能想到的。

// create new array with year as key and numb as value
$res =array();
Foreach($arr as $val){
    If(!isset($res[$val["year"]])) $res[$val["year"]] =0;
    $res[$val["year"]] += $val["numb"];

}

ksort($res); // sort the array on keys to make earliest year first
$newarr= array();
$sum =0;
foreach($res as $key => $val){
    $newarr[$key] = $val+$sum; // new array with summed values from previous year(s)
    $sum +=$val;
}
Var_dump($newarr);

https://3v4l.org/5Ql2U

Answer 4

$dbResult = array(array('year' => '2016', 'numb' => 1),  
                array('year' => '2016', 'numb' => 3), 
                array('year' => '2017', 'numb' => 3), 
                array('year' => '2016', 'numb' => 1), 
                array('year' => '2018', 'numb' => 2)); 

$result = array();
foreach ($dbResult as $data) {
    $result[$data['year']] = (isset($result[$data['year']])) ? $result[$data['year']] : 0;
    $result[$data['year']] = $result[$data['year']] + $data['numb'] ;
}
echo '<pre>';print_r($result);

PHP数组添加增量

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