PHP从键名创建一个多维关联数组

Question

即使它已记录在案，我也需要帮助以更好地理解此代码（仅参考）。我已经检查了教程，但它们没有帮助我。

// initialize variables
$val = 'it works !';
$arr = [];

// Get the keys we want to assign
$keys = [ 'key_1', 'key_2', 'key_3', 'key_4' ];

// Get a reference to where we start
$curr = &$arr;

// Loops over keys
foreach($keys as $key) {
   // get the reference for this key
   $curr = &$curr[$key];
}

// Assign the value to our last reference
$curr = $val;

// visualize the output, so we know its right
var_dump($arr);
echo "<hr><pre>\$arr : "; print_r($arr);

（来源：https://stackoverflow.com/a/31103901/4741362@Derokorian）

Answer 1

我会尝试解释它让你更好地理解它，请参阅工作代码here。我希望它能帮助你理解这个$curr = &$curr[$key]; 行。 $curr 在foreach 开始之前指向空的$arr，在foreach 中，它通过引用将$key 的值保存到$arr 中，该引用由$curr 指向，然后重新分配将$arr 中的$key 新保存到$curr 指针。

// initialize variables
$val = 'it works !';
$arr = [];

// Get the keys we want to assign
$keys = [ 'key_1', 'key_2', 'key_3', 'key_4' ];

// Get a reference to where we start
echo "create a space where to save the first key \r\n";
$curr = &$arr;

// Loops over keys
$i = 1;
foreach($keys as $key) {

    echo "**************** Iteration no $i ******************\r\n";
    // echo "save the value \"$key\" to the reference created earlier in the \$curr variable for the empty array above where the kesy are actually being saved \r\n";

    // get the reference for this key
    echo "Now save the value of \$key to the array reference present in \$curr and then assigne the reference of newly saved array item to \$curr again \r\n";
    $curr = &$curr[$key];
    print_r($arr);

   $i++;
   echo "\r\n\r\n";
}

// Assign the value to our last reference
$curr = $val;

// visualize the output, so we know its right
print_r($arr);