在PHP中，如何计算多维数组中特定键的值？

我有一个如下所示的数组：

数组（
[0]=>数组（[city]=>309[商店]=>12[苹果]=>21[橙子]=>14[荔枝]=>34）
[1] =>数组（[城市]=>309[商店]=>13[苹果]=>0[橙子]=>11[荔枝]=>32）
[2] =>数组（[city]=>309[store]=>14[Apple]=>44[oranges]=>61[lichis]=>0）
[3] =>数组（[城市]=>309[商店]=>15[苹果]=>7[橙子]=>0[荔枝]=>6）
[4] =>数组（[城市]=>309[商店]=>16[苹果]=>0[橙子]=>0[荔枝]=>12） )

这里我需要做两件事：
1.获取城市中所有特定水果的数量（即309城市中总共有多少苹果、桔子、荔枝）和
2.如何获取特定商店的值

---

提前谢谢

好吧，假设数组名为$store

$count = 0;
$s = array();

foreach($store as $store){
 $count = 0;
 $count += $store['apples'];
 $count += $store['oranges'];

 $s[$store['store']] = $count;
}

---

如果需要，添加更多水果。

这是一个更复杂的示例，但比意大利面代码要好。首先将数组转换为XML

// this is your initial array
$my_array = array(
array("city"=>309, "store"=>12, "apples"=>21, "oranges"=>14, "lichis"=>34 ),
array("city"=>309, "store"=>13, "apples"=>0, "oranges"=>11, "lichis"=>32 ),
array("city"=>309, "store"=>14, "apples"=>44, "oranges"=>61, "lichis"=>0 ),
array("city"=>309, "store"=>15, "apples"=>7, "oranges"=>0, "lichis"=>6 ),
array("city"=>309, "store"=>16, "apples"=>0, "oranges"=>0, "lichis"=>12 ),
);

编写意大利面代码来手动隔离存储区会变成一个由if语句和循环组成的混乱丛林

// might as well convert it to xml
function array_to_xml( $data ) {
    $xml = "<xml>\n";
    foreach( $data as $row ) {
        $xml .= "<entry>";
        foreach( $row as $k => $v ) {
            $xml .= "<{$k}>{$v}</{$k}>";
        }
        $xml .= "</entry>\n";
    }
    $xml .= "</xml>\n";
    return( $xml );
}

现在，将其加载到可使用XPath（XML标准）查询的内容中：

$xml = simplexml_load_string( array_to_xml( $my_array ) );

要获得城市中所有特定水果的数量（即城市309中总共有多少苹果、桔子、荔枝），我们需要一个简单但可重用的汇总函数

// so lets make a generic function to count specific items
function count_items( $stores, $items = array() ) {
    $sum = array();
    foreach( $stores as $store ) {
        foreach( $items as $k ) {
            if( !isset( $sum[$k] ) ) $sum[$k] = 0;
            $sum[$k] += $store->$k;
        }
    }
    return( $sum );
}

我们只想要city 309，特别是苹果、桔子和地衣，因为它们是水果：

$only_this_city = $xml->xpath("//entry[city=309]");
print_r( count_items( $only_this_city, array("apples", "oranges", "lichis")) );

我们得到这个：

Array
(
    [apples] => 72
    [oranges] => 86
    [lichis] => 84
)

其次，要获取特定商店的值：

$only_this_store = $xml->xpath("//entry[city=309 and store=14]");
print_r( count_items( $only_this_store, array("apples") ) );

你会得到：

Array
(
    [apples] => 44
)

显然，您可以请求更多的项，或者更复杂的查询。在XPath上查找一些文档以备将来查询

function extractData( array $data, $store = null )
{
    $callback = function( $values, $array ) use ( $store )
    {
        // We require values for a particular store
        if( ! is_null( $store ) )
        {
            if( $array[ 'store' ] == $store )
            {
                return $array;
            }

            return false;
        }
        // Return the sum of all stores in a city
        else
        {
            // Toss out the city and store values since they're not needed
            unset( $array['city'], $array['store'] );

            // Seed the initial values
            if( ! is_array( $values ) || empty( $values ) )
            {
                return $array;
            }

            // array_map function used add the arrays
            $add = function( $a, $b )
            {
                return $a + $b;
            };

            // Add the arrays
            $summedArray = array_map( $add, $values, $array );

            // Return the combined array structure
            return array_combine( array_keys( $values ), $summedArray );
        }
    };

    return array_reduce( $data, $callback, array() );
}

$data = array(
    0 => array(
        "city" => 309,
        "store" => 12,
        "apples" => 21,
        "oranges" => 14,
        "lichis" => 34
    ),
    1 => array(
        "city" => 309,
        "store" => 13,
        "apples" => 0,
        "oranges" => 11,
        "lichis" => 32
    ),
    2 => array(
        "city" => 309,
        "store" => 14,
        "apples" => 44,
        "oranges" => 61,
        "lichis" => 0
    ),
    3 => array(
        "city" => 309,
        "store" => 15,
        "apples" => 7,
        "oranges" => 0,
        "lichis" => 6
    ),
    4 => array(
        "city" => 309,
        "store" => 16,
        "apples" => 0,
        "oranges" => 0,
        "lichis" => 12
    )
);

// Return the values for a particular store
print_r( extractData( $data, 16 ) );

// Return the total of all stores in the city
print_r( extractData( $data ) );

这将产生以下结果

单一城市

Array
(
    [city] => 309
    [store] => 16
    [apples] => 0
    [oranges] => 0
    [lichis] => 12
)

总计

Array
(
    [apples] => 72
    [oranges] => 86
    [lichis] => 84
)

注意：在做出任何反应之前……我知道OP没有询问如何以面向对象的方式处理这个问题，所以这只是一个建议

我将为整个数据创建一个单独的类，为每个存储数据创建另一个类

$arr = array(
    array('city' => 309, 'store' => 12, 'apples' => 21, 'oranges' => 14, 'lichis' => 34),
    array('city' => 309, 'store' => 13, 'apples' => 0, 'oranges' => 11, 'lichis' => 32),
    array('city' => 309, 'store' => 14, 'apples' => 44, 'oranges' => 61, 'lichis' => 0),
    array('city' => 309, 'store' => 15, 'apples' => 7, 'oranges' => 0, 'lichis' => 6),
    array('city' => 309, 'store' => 16, 'apples' => 0, 'oranges' => 0, 'lichis' => 12)
);

foreach ($arr as $rec) {
    $storeID = $rec['store'];
    $city = $rec['city'];
    unset($rec['city'],$rec['store']);
    // assuming all the keys except these 2
    // represent product name->quantity pairs
    StoreData::add(new Store($storeID,$city,$rec));
}
//print_r(StoreData::$stores);

echo
'<b>total products:</b> ' .
    StoreData::get_total_products() . PHP_EOL .
'<b>total products in city #309:</b> ' .
    StoreData::get_total_products_by_city(309) . PHP_EOL .
'<b>"apples" everywhere:</b> ' .
    StoreData::get_product_total('apples') . PHP_EOL .
'<b>"apples" in store #12:</b> ' .
    StoreData::get_product_total_by_store('apples',12) . PHP_EOL .
'<b>"apples" in city #309:</b> ' .
    StoreData::get_product_total_by_city('apples',309);


class StoreData {

    public static $stores = array();

    public static function add(Store $store) {
        self::$stores[] = $store;
    }

    public static function remove(Store $store) {
        foreach (self::$stores as $key => $value) {
            if ($value == $store) {
                unset(self::$stores[$key]);
                break;
            }
        }
    }

    public static function find_by_city($cityID) {
        $cityID = (int) $cityID;
        return array_filter(self::$stores,create_function(
            '$store',
            "return \$store->city == $cityID;")
        );
    }

    public static function find_by_store($storeID) {
        $storeID = (int) $storeID;
        foreach (self::$stores as $store) {
            if ($store->id == $storeID) return $store;
        }
        return FALSE;
    }

    public static function get_total_products() {
        $total = 0;
        foreach (self::$stores as $store)
            $total += $store->get_total_products();
        return $total;
    }

    public static function get_total_products_by_city($city) {
        $stores = self::find_by_city((int) $city);
        $total = 0;
        foreach ($stores as $store)
            $total += $store->get_total_products();
        return $total;
    }

    public static function get_product_total_by_city($productName,$city) {
        return self::product_total($productName,self::find_by_city((int) $city));
    }

    public static function get_product_total_by_store($productName,$storeID) {
        $res = self::find_by_store((int) $storeID);
        return $res ? self::product_total($productName,array($res)) : $res;
    }

    public static function get_product_total($productName) {
        return self::product_total($productName,self::$stores);
    }

    private static function product_total($productName,$stores=NULL) {
        $total = 0;
        foreach ($stores as $store)
            $total += $store->get_product_total($productName);
        return $total;
    }

}

class Store {

    public $id;
    public $city;
    public $products;

    function __construct($id,$city,$products=array()) {
        $this->id = $id;
        $this->city = $city;
        $this->products = $products;
    }

    public function get_total_products() {
        return array_sum($this->products);
    }

    public function get_product_total($productName) {
        if (isset($this->products[$productName]))
            return (int) $this->products[$productName];
        return 0;
    }

}

$arr=array(
数组（'city'=>309，'store'=>12，'Apple'=>21，'oranges'=>14，'lichis'=>34），
数组（'city'=>309，'store'=>13，'Apple'=>0，'oranges'=>11，'lichis'=>32），
数组（'city'=>309，'store'=>14，'Apple'=>44，'oranges'=>61，'lichis'=>0），
数组（'city'=>309，'store'=>15，'Apple'=>7，'oranges'=>0，'lichis'=>6），
数组（'city'=>309，'store'=>16，'Apple'=>0，'oranges'=>0，'lichis'=>12）
);
foreach（$arr作为$rec）{
$storeID=$rec['store']；
$city=$rec['city']；
未设置（$rec['city'，$rec['store']）；
//假设除了这两个键以外的所有键
//表示产品名称->数量对
StoreData：：添加（新商店（$storeID，$city，$rec））；
}
//打印（存储数据：$stores）；
回声
“总产品：”。
StoreData:：get_total_products（）。PHP_EOL。
“城市产品总量”309:”。
StoreData：：按城市获取产品总数（309）。PHP_EOL。
到处都是苹果。
StoreData:：获取产品总数（“苹果”）。PHP_EOL。
"苹果店#12:"。
StoreData：：按商店（“苹果”，12）获取产品总数。PHP_EOL。
城市里的“苹果”。
StoreData：：按城市（“苹果”，309）获取产品总量；
类存储数据{
公共静态$stores=array（）；
公共静态函数add（Store$Store）{
self:：$stores[]=$store；
}
公共静态函数删除（Store$Store）{
foreach（self:：$存储为$key=>$value）{
如果（$value==$store）{
取消设置（self:$stores[$key]）；
打破
}
}
}
公共静态函数按城市查找（$cityID）{
$cityID=（int）$cityID；
返回数组_过滤器（self:：$stores，create_函数(
“$store”，
“return\$store->city==$cityID；”）
);
}
公共静态函数按存储查找存储（$storeID）{
$storeID=（int）$storeID；
foreach（self:：$stores作为$store）{
如果（$store->id==$storeID）返回$store；
}
返回FALSE；
}
公共静态函数get_total_products（）{
$total=0；
foreach（self:：$stores作为$store）
$total+=$store->get_total_products（）；
返回$total；
}
公共静态函数按城市（城市）获取产品总数{
$stores=self：：按城市查找城市（（int）$city）；
$total=0；
foreach（$stores作为$store存储）
$total+=$store->get_total_products（）；
返回$total；
}
公共静态函数按城市获取产品总数（$productName，$city）{
返回self:：product_总计（$productName，self:：按城市查找（（int）$city））；
}
公共静态函数按存储获取产品总数（$productName，$storeID）{
$res=self：：按存储查找存储（（int）$storeID）；
返回$res？self:：product_total（$productName，array（$res））：$res；
}
公共静态函数获取产品总数（$productName）{
返回self:：product_总计（$productName，self:：$stores）；
}
私有静态函数产品\总计（$productName，$stores=NULL）{
$total=0；
foreach（$stores作为$store存储）
$total+=$store->get\u product\u total（$productName）；
返回$total；
}
}
班级商店{
公费$id；
公共城市；
公共产品；
函数构造（$id，$city，$products=array（））{
$this->id=$id；
$this->city=$city；
$this->products=$products；
}
公共函数获取总产品（）{
返回数组的总和（$this->products）；
}
公用函数获取产品总数（$productName）{
如果（isset（$this->products[$productName]））
返回（int）$this->products[$productName]；
返回0；
}
}

将输出

产品总数：242
全市产品总量#309:242
到处都是苹果：72
商店里的“苹果”#12:21
城市中的“苹果”#3

$arr = array(
    array('city' => 309, 'store' => 12, 'apples' => 21, 'oranges' => 14, 'lichis' => 34),
    array('city' => 309, 'store' => 13, 'apples' => 0, 'oranges' => 11, 'lichis' => 32),
    array('city' => 309, 'store' => 14, 'apples' => 44, 'oranges' => 61, 'lichis' => 0),
    array('city' => 309, 'store' => 15, 'apples' => 7, 'oranges' => 0, 'lichis' => 6),
    array('city' => 309, 'store' => 16, 'apples' => 0, 'oranges' => 0, 'lichis' => 12)
);

foreach ($arr as $rec) {
    $storeID = $rec['store'];
    $city = $rec['city'];
    unset($rec['city'],$rec['store']);
    // assuming all the keys except these 2
    // represent product name->quantity pairs
    StoreData::add(new Store($storeID,$city,$rec));
}
//print_r(StoreData::$stores);

echo
'<b>total products:</b> ' .
    StoreData::get_total_products() . PHP_EOL .
'<b>total products in city #309:</b> ' .
    StoreData::get_total_products_by_city(309) . PHP_EOL .
'<b>"apples" everywhere:</b> ' .
    StoreData::get_product_total('apples') . PHP_EOL .
'<b>"apples" in store #12:</b> ' .
    StoreData::get_product_total_by_store('apples',12) . PHP_EOL .
'<b>"apples" in city #309:</b> ' .
    StoreData::get_product_total_by_city('apples',309);


class StoreData {

    public static $stores = array();

    public static function add(Store $store) {
        self::$stores[] = $store;
    }

    public static function remove(Store $store) {
        foreach (self::$stores as $key => $value) {
            if ($value == $store) {
                unset(self::$stores[$key]);
                break;
            }
        }
    }

    public static function find_by_city($cityID) {
        $cityID = (int) $cityID;
        return array_filter(self::$stores,create_function(
            '$store',
            "return \$store->city == $cityID;")
        );
    }

    public static function find_by_store($storeID) {
        $storeID = (int) $storeID;
        foreach (self::$stores as $store) {
            if ($store->id == $storeID) return $store;
        }
        return FALSE;
    }

    public static function get_total_products() {
        $total = 0;
        foreach (self::$stores as $store)
            $total += $store->get_total_products();
        return $total;
    }

    public static function get_total_products_by_city($city) {
        $stores = self::find_by_city((int) $city);
        $total = 0;
        foreach ($stores as $store)
            $total += $store->get_total_products();
        return $total;
    }

    public static function get_product_total_by_city($productName,$city) {
        return self::product_total($productName,self::find_by_city((int) $city));
    }

    public static function get_product_total_by_store($productName,$storeID) {
        $res = self::find_by_store((int) $storeID);
        return $res ? self::product_total($productName,array($res)) : $res;
    }

    public static function get_product_total($productName) {
        return self::product_total($productName,self::$stores);
    }

    private static function product_total($productName,$stores=NULL) {
        $total = 0;
        foreach ($stores as $store)
            $total += $store->get_product_total($productName);
        return $total;
    }

}

class Store {

    public $id;
    public $city;
    public $products;

    function __construct($id,$city,$products=array()) {
        $this->id = $id;
        $this->city = $city;
        $this->products = $products;
    }

    public function get_total_products() {
        return array_sum($this->products);
    }

    public function get_product_total($productName) {
        if (isset($this->products[$productName]))
            return (int) $this->products[$productName];
        return 0;
    }

}