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
根据您的要求“每个值只能出现一次”,如果您只是想在数组中保持唯一的值,那么array_unique()可能就是您正在寻找的。
输入:
$input = array(4, "4", "3", 4, 3, "3");
$result = array_unique($input);
var_dump($result);
结果:
array(2) {
[0] => int(4)
[2] => string(1) "3"
}
其他回答
或者简单地说,手动方式:
foreach ($array as $key => $value){
if ($value == $target_value) {
unset($array[$key]);
}
}
这是最安全的,因为你可以完全控制你的阵列
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)
}
使用or操作符的一行代码:
($key = array_search($del_val, $messages)) !== false or unset($messages[$key]);
根据您的要求“每个值只能出现一次”,如果您只是想在数组中保持唯一的值,那么array_unique()可能就是您正在寻找的。
输入:
$input = array(4, "4", "3", 4, 3, "3");
$result = array_unique($input);
var_dump($result);
结果:
array(2) {
[0] => int(4)
[2] => string(1) "3"
}
借用了underscore.JS _的逻辑。拒绝并创建了两个函数(人们更喜欢函数!!)
array_reject_value:该函数简单地拒绝指定的值(也适用于PHP4,5,7)
function array_reject_value(array &$arrayToFilter, $deleteValue) {
$filteredArray = array();
foreach ($arrayToFilter as $key => $value) {
if ($value !== $deleteValue) {
$filteredArray[] = $value;
}
}
return $filteredArray;
}
array_reject:这个函数只是拒绝可调用方法(适用于PHP >=5.3)
function array_reject(array &$arrayToFilter, callable $rejectCallback) {
$filteredArray = array();
foreach ($arrayToFilter as $key => $value) {
if (!$rejectCallback($value, $key)) {
$filteredArray[] = $value;
}
}
return $filteredArray;
}
所以在我们当前的例子中,我们可以像下面这样使用上述函数:
$messages = [312, 401, 1599, 3, 6];
$messages = array_reject_value($messages, 401);
或者甚至更好:(因为这给了我们更好的语法使用,比如array_filter)
$messages = [312, 401, 1599, 3, 6];
$messages = array_reject($messages, function ($value) {
return $value === 401;
});
上面的代码可以用于更复杂的事情,比如我们想要删除所有大于或等于401的值,我们可以简单地这样做:
$messages = [312, 401, 1599, 3, 6];
$greaterOrEqualThan = 401;
$messages = array_reject($messages, function ($value) use $greaterOrEqualThan {
return $value >= $greaterOrEqualThan;
});