构建数组路径

Question

我正在尝试构建数组路径以减少代码。原因是有大约 50 条长路径，我想减少代码库。对于“test-2”，变量“$path”可以被硬编码，同时右侧“key-X”应该能够调整，例如用于以后的 for 循环。问题：是否可以构建“test-2”中描述的数组路径？想要的结果：测试 1：60测试 2：60<?php$arrayWithPrettyLongName = [  'level_1' => [    'key_1' => 10,    'key_2' => 20,    'key_3' => 30,  ]];// Test-1 // Works fine!$result_1 =$arrayWithPrettyLongName['level_1']['key_1'] +$arrayWithPrettyLongName['level_1']['key_2'] +$arrayWithPrettyLongName['level_1']['key_3'] ;echo $result_1;// Test-2 // Throws errors.$path = "$arrayWithPrettyLongName['level_1']";$result_2 =$path . ['key_1'] +$path . ['key_2'] +$path . ['key_3'] ;echo $result_2;错误PHP Parse error:  syntax error, unexpected '' (T_ENCAPSED_AND_WHITESPACE), expecting '-' or identifier (T_STRING) or variable (T_VARIABLE) or number (T_NUM_STRING) in Xxx.php on line 18

Answer 1

我认为您真正想知道的是如何创建数组引用。您可以通过在数组名称前添加 & 符号来实现此目的

<?php

$arrayWithPrettyLongName = [

  'level_1' => [

    'key_1' => 10,

    'key_2' => 20,

    'key_3' => 30,

  ]

];

// Test-1 // Works fine!

$result_1 =

$arrayWithPrettyLongName['level_1']['key_1'] +

$arrayWithPrettyLongName['level_1']['key_2'] +

$arrayWithPrettyLongName['level_1']['key_3'] ;

echo $result_1;

echo "\n";

//Just create an array reference here, by preceding the name with an `&`

$path = &$arrayWithPrettyLongName['level_1'];

//Also remove the `.` symbol here. That's not the correct syntax

$result_2 =

$path['key_1'] +

$path['key_2'] +

$path['key_3'] ;

echo $result_2;

但看！如果你真的想减少代码，难道就不能这样做吗？

$result_3 = 0;

foreach ($arrayWithPrettyLongName['level_1'] as $value){

    $result_3 += $value;

}

echo $result_3;

如果以后数组变大，保存就会很麻烦。

Answer 2

像这里一样工作：

    <?php

$arrayWithPrettyLongName = [

  'level_1' => [

    'key_1' => 10,

    'key_2' => 20,

    'key_3' => 30,

  ]

];

// Test-1

$result_1 =

$arrayWithPrettyLongName['level_1']['key_1'] +

$arrayWithPrettyLongName['level_1']['key_2'] +

$arrayWithPrettyLongName['level_1']['key_3'] ;

echo $result_1; //output 60

// Test-2

$path = $arrayWithPrettyLongName['level_1'];

$result_2 =

$path['key_1'] +

$path['key_2'] +

$path['key_3'] ;

echo $result_2; //output 60

?>

你错了$path = "$arrayWithPrettyLongName['level_1']";必须是没有""

另一个改变是$path .必须是$path['key_1'];