Php 如果我们有数组索引的概念，如何使用array\u column函数从数组中获取记录？

我有一系列的加密硬币利率。 阵列的外观如下所示：

$array = Array ( [0] => Array ( [code] => BTC [name] => Bitcoin [rate] => 1 )
 [1] => Array ( [code] => BCH [name] => Bitcoin Cash [rate] => 7.06364 )
 [2] => Array ( [code] => USD [name] => US Dollar [rate] => 8185.84 ) )

我使用

$array[1]['rate']获得结果

但我想通过[代码]得到结果

像
$array['USD']['rate']

像
$array['BCH']['rate']

如何使用货币代码获取汇率，例如美元
您可以循环数组并构建一个新的关联数组以用于项目的其余部分

$array = Array( 0 => Array( "code" => "BTC", "name" => "Bitcoin", "rate" => 1 ),
 "1" => Array ( "code" => "BCH", "name" => "Bitcoin Cash", "rate" => 7.06364 ),
 "2" => Array ( "code" => "USD", "name" => "US Dollar", "rate" => 8185.84 ) );

 foreach($array as $val){
     $rates[$val["code"]] = $val;
 }

 echo $rates['USD']['rate']; // 8185.84



另一种选择是使用array\u column和array\u组合来完成，而不使用循环

$array = Array( 0 => Array( "code" => "BTC", "name" => "Bitcoin", "rate" => 1 ),
 "1" => Array ( "code" => "BCH", "name" => "Bitcoin Cash", "rate" => 7.06364 ),
 "2" => Array ( "code" => "USD", "name" => "US Dollar", "rate" => 8185.84 ) );

 $keys = array_column($array, "code");
 $rates = array_combine($keys, $array);

 echo $rates['USD']['rate'];

您可以在回调函数中使用键并将其设置为
code
的值：

$array = array_reduce($array, function($carry, $item) {
    $carry[$item["code"]] = $item;
    return $carry;
});

echo $array["USD"]["rate"]; //8185.84

可能存在的副本