php 删除一维数组中某一个值元素的操作方法

<?php
$tmp = '324';
$arr = array(
'0' => '321',
'1' => '322',
'2' => '323',
'3' => '324',
'4' => '325',
'5' => '326',
);

foreach( $arr as $k=>$v) {
 if($tmp == $v) unset($arr[$k]);
}
print_r($arr);
?>

Array
(
 [0] => 321
 [1] => 322
 [2] => 323
 [4] => 325
 [5] => 326
)

foreach( $arr as $k=>$v) {
 if($tmp == $v) unset($arr[$k]);
}
$arr = array_values($arr);
print_r($arr);
?>

Array
(
 [0] => 321
 [1] => 322
 [2] => 323
 [3] => 325
 [4] => 326
)

foreach( $arr as $k=>$v) {
 if($tmp == $v) unset($arr[$k]);
}
$arr = array_merge($arr);
print_r($arr);
?>

Array
(
 [0] => 321
 [1] => 322
 [2] => 323
 [3] => 325
 [4] => 326
)

$key=array_search($tmp ,$arr);
array_splice($arr,$key,1);
var_dump($arr);

Array
(
 [0] => 321
 [1] => 322
 [2] => 323
 [3] => 325
 [4] => 326
)

$arr = array_merge(array_diff($arr, array($tmp)));
var_dump($arr);

Array
(
 [0] => 321
 [1] => 322
 [2] => 323
 [3] => 325
 [4] => 326
)

$arr = array_merge(array_diff($arr, $tmp));
var_dump($arr);