我有一个PHP数组如下:
$messages = [312, 401, 1599, 3, ...];
我想删除包含值$del_val的元素(例如,$del_val=401),但我不知道它的键。这可能会有帮助:每个值只能在那里出现一次。
我正在寻找执行这项任务的最简单的函数。
我有一个PHP数组如下:
$messages = [312, 401, 1599, 3, ...];
我想删除包含值$del_val的元素(例如,$del_val=401),但我不知道它的键。这可能会有帮助:每个值只能在那里出现一次。
我正在寻找执行这项任务的最简单的函数。
当前回答
要删除多个值,试试这个:
while (($key = array_search($del_val, $messages)) !== false)
{
unset($messages[$key]);
}
其他回答
在PHP 7.4中使用箭头函数:
$messages = array_filter($messages, fn ($m) => $m != $del_val);
为了保持它是一个非关联数组,用array_values()来包装它:
$messages = array_values(array_filter($messages, fn ($m) => $m != $del_val));
一个有趣的方法是使用array_keys():
foreach (array_keys($messages, 401, true) as $key) {
unset($messages[$key]);
}
array_keys()函数接受两个额外的参数,只返回特定值的键,以及是否需要严格检查(即使用===进行比较)。
这也可以删除具有相同值的多个数组项(例如[1,2,3,3,4])。
要删除多个值,试试这个:
while (($key = array_search($del_val, $messages)) !== false)
{
unset($messages[$key]);
}
我认为最简单的方法是使用带有foreach循环的函数:
//This functions deletes the elements of an array $original that are equivalent to the value $del_val
//The function works by reference, which means that the actual array used as parameter will be modified.
function delete_value(&$original, $del_val)
{
//make a copy of the original, to avoid problems of modifying an array that is being currently iterated through
$copy = $original;
foreach ($original as $key => $value)
{
//for each value evaluate if it is equivalent to the one to be deleted, and if it is capture its key name.
if($del_val === $value) $del_key[] = $key;
};
//If there was a value found, delete all its instances
if($del_key !== null)
{
foreach ($del_key as $dk_i)
{
unset($original[$dk_i]);
};
//optional reordering of the keys. WARNING: only use it with arrays with numeric indexes!
/*
$copy = $original;
$original = array();
foreach ($copy as $value) {
$original[] = $value;
};
*/
//the value was found and deleted
return true;
};
//The value was not found, nothing was deleted
return false;
};
$original = array(0,1,2,3,4,5,6,7,4);
$del_val = 4;
var_dump($original);
delete_value($original, $del_val);
var_dump($original);
输出将是:
array(9) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(2)
[3]=>
int(3)
[4]=>
int(4)
[5]=>
int(5)
[6]=>
int(6)
[7]=>
int(7)
[8]=>
int(4)
}
array(7) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(2)
[3]=>
int(3)
[5]=>
int(5)
[6]=>
int(6)
[7]=>
int(7)
}
如果你不知道它的键,那就意味着它无关紧要。
你可以将值作为键,这意味着它会立即找到值。比在所有元素中反复搜索要好。
$messages=array();
$messages[312] = 312;
$messages[401] = 401;
$messages[1599] = 1599;
$messages[3] = 3;
unset($messages[3]); // no search needed