php 搜索数组中的最高键/索引
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Search for highest key/index in an array
提问by Raffael Luthiger
How can I get with PHP the highest key/index in an array? I know how to do it for the values.
如何使用 PHP 获得数组中的最高键/索引？我知道如何为价值观做到这一点。
E.g. From this array I would like to get "10" as an integer value:
例如，从这个数组我想得到“10”作为一个整数值：
$arr = array( 1 => "A", 10 => "B", 5 => "C" );
I know how I could program it, but I was asking myself if there as a function for this as well.
我知道如何对其进行编程，但我问自己是否也有此功能。
回答by Gérald Cro?s
This should work fine
这应该可以正常工作
$arr = array( 1 => "A", 10 => "B", 5 => "C" );
max(array_keys($arr));
回答by Fabrizio D'Ammassa
You can get the maximum key this way:
您可以通过以下方式获得最大密钥：
<?php
$arr = array("a"=>"test", "b"=>"ztest");
$max = max(array_keys($arr));
?>
回答by JG Estiot
I had a situation where I needed to obtain the next available key in an array, which is the highest+1.
我遇到过需要获取数组中下一个可用键的情况，即最高的+1。
For example, if the array is $data=['1'=>'something,'34'=>'something else'] then I needed to calculate 35 to add a new element to the array that had a key higher than any of the others. In the case of an empty array I needed 1 as next available key.
例如，如果数组是 $data=['1'=>'something,'34'=>'something else'] 那么我需要计算 35 以向数组中添加一个新元素，该元素的键高于任何其他人。在空数组的情况下，我需要 1 作为下一个可用键。
This is the solution that worked:
这是有效的解决方案：
$highest = 0;
foreach($data as $idx=>$dummy)
{
if($idx > $highest)$highest=$idx;
}
$highest++;
It will work in all cases, empty array or not. If you only need to find the highest key rather than highest key + 1, delete the last line. You will then get a value of 0 if the array is empty.
无论是否为空数组，它都适用于所有情况。如果只需要查找最高键而不是最高键+1，则删除最后一行。如果数组为空，则您将获得值 0。
回答by Cfreak
$keys = array_keys($arr);
$keys = rsort($keys);
print $keys[0];
should print "10"
应该打印“10”
回答by AllisonC
Try max(): http://php.net/manual/en/function.max.phpSee the first comment on that page
试试 max(): http://php.net/manual/en/function.max.php看那个页面的第一条评论
