我使用in_array()来检查一个值是否存在于如下数组中,
$a = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $a))
{
echo "Got Irix";
}
//print_r($a);
但是对于一个多维数组(下面)——我如何检查这个值是否存在于多数组中?
$b = array(array("Mac", "NT"), array("Irix", "Linux"));
print_r($b);
或者我不应该使用in_array()当涉及到多维数组?
如果你知道要搜索哪一列,你可以使用array_search()和array_column():
$userdb = Array
(
(0) => Array
(
('uid') => '100',
('name') => 'Sandra Shush',
('url') => 'urlof100'
),
(1) => Array
(
('uid') => '5465',
('name') => 'Stefanie Mcmohn',
('url') => 'urlof5465'
),
(2) => Array
(
('uid') => '40489',
('name') => 'Michael',
('url') => 'urlof40489'
)
);
if(array_search('urlof5465', array_column($userdb, 'url')) !== false) {
echo 'value is in multidim array';
}
else {
echo 'value is not in multidim array';
}
这个想法在PHP手册中array_search()的评论部分;
我发现下面的解决方案不是很干净的代码,但它的工作。它被用作递归函数。
function in_array_multi( $needle, $array, $strict = false ) {
foreach( $array as $value ) { // Loop thorugh all values
// Check if value is aswell an array
if( is_array( $value )) {
// Recursive use of this function
if(in_array_multi( $needle, $value )) {
return true; // Break loop and return true
}
} else {
// Check if value is equal to needle
if( $strict === true ) {
if(strtolower($value) === strtolower($needle)) {
return true; // Break loop and return true
}
}else {
if(strtolower($value) == strtolower($needle)) {
return true; // Break loop and return true
}
}
}
}
return false; // Nothing found, false
}
$userdb = Array
(
(0) => Array
(
('uid') => '100',
('name') => 'Sandra Shush',
('url') => 'urlof100'
),
(1) => Array
(
('uid') => '5465',
('name') => 'Stefanie Mcmohn',
('url') => 'urlof5465'
),
(2) => Array
(
('uid') => '40489',
('name') => 'Michael',
('url') => 'urlof40489'
)
);
$url_in_array = in_array('urlof5465', array_column($userdb, 'url'));
if($url_in_array) {
echo 'value is in multidim array';
}
else {
echo 'value is not in multidim array';
}
In_array()在多维数组上不起作用。你可以写一个递归函数来做这件事:
function in_array_r($needle, $haystack, $strict = false) {
foreach ($haystack as $item) {
if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {
return true;
}
}
return false;
}
用法:
$b = array(array("Mac", "NT"), array("Irix", "Linux"));
echo in_array_r("Irix", $b) ? 'found' : 'not found';