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php - 构建数组路径

问题描述

我正在尝试构建数组路径以减少代码。原因是大约有 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，同时右侧的“key-X”应该能够被调整，例如用于以后的for循环。

问题：

是否可以按照“test-2”中的描述构建数组路径？

想要的结果：

测试一：60

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

标签： phparrayspathphp-7.3

解决方案

我认为您在这里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加上 & 符号来做到这一点

<?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，你不能这样做吗？

$result_3 = 0;
foreach ($arrayWithPrettyLongName['level_1'] as $value){
    $result_3 += $value;
}
echo $result_3;

如果以后数组变大，保存会很麻烦。

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