PHP 中带键的数组映射
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Array mapping in PHP with keys
提问by lorenzo-s
Just for curiosity (I know it can be a single line foreachstatement), is there some PHP array function (or a combination of many) that given an array like:
只是出于好奇（我知道它可以是单行foreach语句），是否有一些 PHP 数组函数（或多个函数的组合）给出了一个数组，例如：
Array (
[0] => stdClass Object (
[id] => 12
[name] => Lorem
[email] => [email protected]
)
[1] => stdClass Object (
[id] => 34
[name] => Ipsum
[email] => [email protected]
)
)
And, given 'id'and 'name', produces something like:
并且，给定'id'and 'name'，产生类似的东西：
Array (
[12] => Lorem
[34] => Ipsum
)
I use this pattern a lot, and I noticed that array_mapis quite useless in this scenario cause you can't specify keys for returned array.
我经常使用这种模式，我注意到array_map在这种情况下这非常无用，因为您无法为返回的数组指定键。
回答by moonwave99
Just use array_reduce:
只需使用array_reduce：
$obj1 = new stdClass;
$obj1 -> id = 12;
$obj1 -> name = 'Lorem';
$obj1 -> email = '[email protected]';
$obj2 = new stdClass;
$obj2 -> id = 34;
$obj2 -> name = 'Ipsum';
$obj2 -> email = '[email protected]';
$reduced = array_reduce(
// input array
array($obj1, $obj2),
// fold function
function(&$result, $item){
// at each step, push name into $item->id position
$result[$item->id] = $item->name;
return $result;
},
// initial fold container [optional]
array()
);
It's a one-liner out of comments ^^
这是一个单行评论^^
回答by lorenzo-s
I found I can do:
我发现我可以做到：
array_combine(array_map(function($o) { return $o->id; }, $objs), array_map(function($o) { return $o->name; }, $objs));
But it's ugly and requires two whole cycles on the same array.
但它很丑陋，需要在同一个阵列上进行两个完整的循环。
回答by Josua Marcel Chrisano
Because your array is array of object then you can call (its like a variable of class) try to call with this:
因为你的数组是对象数组，所以你可以调用（它就像一个类变量）尝试用这个调用：
foreach ($arrays as $object) {
Echo $object->id;
Echo "<br>";
Echo $object->name;
Echo "<br>";
Echo $object->email;
Echo "<br>";
}
Then you can do
然后你可以做
// your array of object example $arrays;
$result = array();
foreach ($arrays as $array) {
$result[$array->id] = $array->name;
}
echo "<pre>";
print_r($result);
echo "</pre>";
Sorry I'm answering on handphone. Can't edit the code
对不起，我是用手机接听的。无法编辑代码
回答by Athari
The easiest way is to use a LINQ port like YaLinqolibrary*. It allows performing SQL-like queries on arrays and objects. Its toDictionaryfunction accepts two callbacks: one returning key of the result array, and one returning value. For example:
最简单的方法是使用 LINQ 端口，如YaLinqo库*。它允许对数组和对象执行类似 SQL 的查询。它的toDictionary函数接受两个回调：一个返回结果数组的键，一个返回值。例如：
$userNamesByIds = from($users)->toDictionary(
function ($u) { return $u->id; },
function ($u) { return $u->name; }
);
Or you can use a shorter syntax using strings, which is equivalent to the above version:
或者您可以使用字符串使用更短的语法，这相当于上面的版本：
$userNamesByIds = from($users)->toDictionary('$v->id', '$v->name');
If the second argument is omitted, objects themselves will be used as values in the result array.
如果省略第二个参数，则对象本身将用作结果数组中的值。
* developed by me
* 由我开发
回答by Sachin Sarola
The easiest way is to use an array_column()
最简单的方法是使用 array_column()
$result_arr = array_column($arr, 'name', 'id');
print_r($result_arr );
