新函数 array_column< /a> 非常通用，它可以做的事情之一就是这种类型的重新索引：
array_column
// second parameter is null means we 're just going to reindex the input $usersById = array_column($users, null, 'Id');
您需要使用 array_map，然后使用 array_combine：
array_map
array_combine
$ids = array_map(function($user) { return $user['Id']; }, $users); $users = array_combine($ids, $users);
上面的代码需要 PHP > ;= 5.3 对于匿名函数语法，但是您也可以使用 < 执行相同操作（尽管看起来有点难看） code>create_function 仅需要 PHP >= 4.0.1：
$ids = array_map(create_function('$user', 'return $user["Id"];'), $users); $users = array_combine($ids, $users);
查看它行动。
The new function array_column is very versatile and one of the things it can do is exactly this type of reindexing:
You need to fetch the ids from the sub-arrays with array_map, then create a new array with array_combine:
The code above requires PHP >= 5.3 for the anonymous function syntax, but you can also do the same (albeit it will look a bit uglier) with create_function which only requires PHP >= 4.0.1:
create_function
See it in action.
您可以使用 array_reduce() 函数，例如：
array_reduce()
$usersById = array_reduce($users, function ($reduced, $current) { $reduced[$current['Id']] = $current; return $reduced; });
但是，它并不比一个foreach。
foreach
You could use the array_reduce() function, like:
However, it's no more elegant than a foreach.
我认为使用 foreach 更加优雅。也许你只是想以不同的方式编写它：
$keyed = array(); foreach($users as $w) $keyed[$w['Id']] = $w;
如果你想替换现有的数组，foreach确实不是那么灵活。但也许以下是某种替代方案：
$users = function($key) use ($users) { foreach($users as $v) $keys[] = $v[$key]; return array_combine($keys, $users); }; $users = $users('Id');
它允许回调接受参数，例如用于创建新密钥的密钥名称。
I think using foreach is much more elegant. Maybe you just only want to write it differently:
In case you want to replace the existing array, foreach is not that flexible indeed. But maybe the following is some sort of alternative:
It allows the callback to accept parameters, e.g. the name of the key which should be used to create the new keys from.
还有一种使用 array_walk 的变体：
$usersById = array(); array_walk($users, function($val) use (&$usersById) { $usersById[$val['Id']] = $val; });
And one more variant using array_walk:
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现代答案（需要 PHP 5.5）
新函数
array_column< /a> 非常通用，它可以做的事情之一就是这种类型的重新索引：原始答案（对于早期的 PHP 版本）
您需要使用
array_map，然后使用array_combine：上面的代码需要 PHP > ;= 5.3 对于匿名函数语法，但是您也可以使用 < 执行相同操作（尽管看起来有点难看） code>create_function 仅需要 PHP >= 4.0.1：
查看它行动。
Modern answer (requires PHP 5.5)
The new function
array_columnis very versatile and one of the things it can do is exactly this type of reindexing:Original answer (for earlier PHP versions)
You need to fetch the ids from the sub-arrays with
array_map, then create a new array witharray_combine:The code above requires PHP >= 5.3 for the anonymous function syntax, but you can also do the same (albeit it will look a bit uglier) with
create_functionwhich only requires PHP >= 4.0.1:See it in action.
您可以使用
array_reduce()函数，例如：但是，它并不比一个
foreach。You could use the
array_reduce()function, like:However, it's no more elegant than a
foreach.我认为使用
foreach更加优雅。也许你只是想以不同的方式编写它：如果你想替换现有的数组，
foreach确实不是那么灵活。但也许以下是某种替代方案：它允许回调接受参数，例如用于创建新密钥的密钥名称。
I think using
foreachis much more elegant. Maybe you just only want to write it differently:In case you want to replace the existing array,
foreachis not that flexible indeed. But maybe the following is some sort of alternative:It allows the callback to accept parameters, e.g. the name of the key which should be used to create the new keys from.
还有一种使用 array_walk 的变体：
And one more variant using array_walk: