php 取消设置数组的最后一项
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unset last item of array
提问by AmirModiri
in this code i try to unset first and last item of $status array
to unset but the last item that i tried place thier pointer in $end
not unset what can I do for this reason?
在这段代码中，我尝试取消设置 $status 数组的第一项和最后一项
以取消设置，但我尝试将其指针放在 $end 中的最后一项
没有取消设置，出于这个原因我该怎么办？
$item[$fieldneedle] = " node_os_disk_danger ";
$status = preg_split('/_/',$item[$fieldneedle]);
unset($status[0]);
$end = & end($status);
unset($end);
in this example i need os_disk
在这个例子中我需要 os_disk
回答by Diablo
array_shift($end); //removes first
array_pop($end); //removes last
回答by GolezTrol
Use explodeinstead of preg_split. It is faster.
Then you can use array_popand array_shiftto remove an item from the end and beginning of the array. Then, use implodeto put the remaining items back together again.
使用explode代替preg_split。它更快。然后您可以使用array_pop和array_shift从数组的末尾和开头删除一个项目。然后，使用implode将剩余的物品重新组合在一起。
A better solution would be to use str_posto find the first and last _and use substrto copy the part inbetween. This will cause only one sting copy, instead of having to transform a string to array, modify that, and put the array together into a string. (Or don't you need to put them together? The 'I need 'os_disk' at the end confuses me).
更好的解决方案是使用str_pos查找第一个和最后一个_并使用substr复制中间的部分。这将只导致一个 sting 副本，而不必将字符串转换为数组，修改它，然后将数组组合成一个字符串。（或者你不需要把它们放在一起吗？最后的'我需要'os_disk'让我感到困惑）。
回答by Savetheinternet
$item[$fieldneedle] = " node_os_disk_danger ";
$status = preg_split('/_/',$item[$fieldneedle]);
$status = array_slice($status, 1, -1);
回答by ircmaxell
Well, if you want the result to be a string, why bother converting to a string?
好吧，如果你希望结果是一个字符串，为什么还要转换成一个字符串呢？
$regex = '#^[^_]*_(.*?)_[^_]*$#';
$string = preg_replace($regex, '\1', $string);
It replaces everything up to and including the first underscore character, and everything after and including the last underscore character. Nice, easy and efficient...
它替换包括第一个下划线字符在内的所有内容，以及最后一个下划线字符之后和包括的所有内容。漂亮，简单，高效...
回答by Priyank
You can also use unset to remove last or any item with key
您还可以使用 unset 删除最后一个或任何带有键的项目
unset($status[0]); // removes the first item
unset($status[count($status) - 1]); // removes the last item
回答by Toto
With regex, you can do:
使用正则表达式，您可以：
$item[$fieldneedle] = preg_replace("/^[^_]+_(.+)_[^_]+$/", "", $item[$fieldneedle]);
regex:
正则表达式：
^ : begining of the string
[^_]+ : 1 or more non _
_ : _
(.+) : capture 1 or more characters
_ : _
[^_]+ : 1 or more non _
$ : end of string
