php 如何从相应的数组值中获取数组键？
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How to get array key from corresponding array value?
提问by JD Isaacks
You can easily get an array value by its key like so: $value = array[$key]but what if I have the value and I want its key. What's the best way to get it?
您可以通过其键轻松获取数组值，如下所示：$value = array[$key]但是如果我有该值并且我想要它的键呢？获得它的最佳方法是什么？
回答by Pekka
You could use array_search()to find the first matching key.
您可以array_search()用来查找第一个匹配的键。
From the manual:
从手册：
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');
$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array); // $key = 1;
回答by Sarfraz
You can use the array_keysfunction for that.
您可以array_keys为此使用该功能。
Example:
例子：
$array = array("blue", "red", "green", "blue", "blue");
print_r(array_keys($array, "blue"));
This will get the key from the array for value blue
这将从数组中获取键值 blue
回答by fkaufusi
$arr = array('mango', 'orange', 'banana');
$a = array_flip($arr);
$key = $a['orange'];
回答by barrycarter
No really easy way. Loop through the keys until you find array[$key] == $value
没有真正简单的方法。遍历键直到找到 array[$key] == $value
If you do this often, create a reverse array/hash that maps values back to keys. Keep in mind multiple keys may map to a single value.
如果您经常这样做，请创建一个将值映射回键的反向数组/哈希。请记住，多个键可能映射到单个值。
回答by sushil bharwani
Your array values can be duplicates so it wont give you exact keys. However the way i think is fine is like iterate over and read the keys
您的数组值可能是重复的，因此它不会为您提供确切的键。但是我认为很好的方式就像迭代并阅读密钥
