php in_array() 和多维数组
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in_array() and multidimensional array
提问by laukok
I use in_array()to check whether a value exists in an array like below,
我in_array()用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);
but what about an multidimensional array (below) - how can I check that value whether it exists in the multi-array?
但是多维数组（如下）如何 - 我如何检查该值是否存在于多数组中？
$b = array(array("Mac", "NT"), array("Irix", "Linux"));
print_r($b);
or I shouldn't be using in_array()when comes to the multidimensional array?
或者我不应该使用in_array()多维数组？
回答by jwueller
in_array()does not work on multidimensional arrays. You could write a recursive function to do that for you:
in_array()不适用于多维数组。您可以编写一个递归函数来为您执行此操作：
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;
}
Usage:
用法：
$b = array(array("Mac", "NT"), array("Irix", "Linux"));
echo in_array_r("Irix", $b) ? 'found' : 'not found';
回答by ethmz
If you know which column to search against, you can use array_search() and array_column():
如果您知道要搜索的列，则可以使用 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';
}
This idea is in the comments section for array_search() on the PHP manual;
这个想法在 PHP 手册中 array_search() 的注释部分；
回答by NassimPHP
This will work too.
这也会起作用。
function in_array_r($item , $array){
return preg_match('/"'.preg_quote($item, '/').'"/i' , json_encode($array));
}
Usage:
用法：
if(in_array_r($item , $array)){
// found!
}
回答by Alan Geleynse
This will do it:
这将做到：
foreach($b as $value)
{
if(in_array("Irix", $value, true))
{
echo "Got Irix";
}
}
in_arrayonly operates on a one dimensional array, so you need to loop over each sub array and run in_arrayon each.
in_array仅对一维数组进行操作，因此您需要遍历每个子数组并在每个子数组上运行in_array。
As others have noted, this will only for for a 2-dimensional array. If you have more nested arrays, a recursive version would be better. See the other answers for examples of that.
正如其他人所指出的，这仅适用于二维数组。如果您有更多的嵌套数组，递归版本会更好。有关示例，请参阅其他答案。
回答by rynhe
if your array like this
如果你的数组是这样的
$array = array(
array("name" => "Robert", "Age" => "22", "Place" => "TN"),
array("name" => "Henry", "Age" => "21", "Place" => "TVL")
);
Use this
用这个
function in_multiarray($elem, $array,$field)
{
$top = sizeof($array) - 1;
$bottom = 0;
while($bottom <= $top)
{
if($array[$bottom][$field] == $elem)
return true;
else
if(is_array($array[$bottom][$field]))
if(in_multiarray($elem, ($array[$bottom][$field])))
return true;
$bottom++;
}
return false;
}
example : echo in_multiarray("22", $array,"Age");
例子 ： echo in_multiarray("22", $array,"Age");
回答by Mukesh Goyal
$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($url_in_array) {
echo 'value is in multidim array';
}
else {
echo 'value is not in multidim array';
}
回答by Fernando
Great function, but it didnt work for me until i added the if($found) { break; }to the elseif
很棒的功能，但是直到我将它添加if($found) { break; }到elseif
function in_array_r($needle, $haystack) {
$found = false;
foreach ($haystack as $item) {
if ($item === $needle) {
$found = true;
break;
} elseif (is_array($item)) {
$found = in_array_r($needle, $item);
if($found) {
break;
}
}
}
return $found;
}
回答by Mohd Abdul Mujib
For Multidimensional Children:in_array('needle', array_column($arr, 'key'))
对于多维儿童：in_array('needle', array_column($arr, 'key'))
For One Dimensional Children:in_array('needle', call_user_func_array('array_merge', $arr))
对于一维儿童：in_array('needle', call_user_func_array('array_merge', $arr))
回答by Mohd Abdul Mujib
You could always serialize your multi-dimensional array and do a strpos:
您始终可以序列化多维数组并执行以下操作strpos：
$arr = array(array("Mac", "NT"), array("Irix", "Linux"));
$in_arr = (bool)strpos(serialize($arr),'s:4:"Irix";');
if($in_arr){
echo "Got Irix!";
}
Various docs for things I used:
我使用过的东西的各种文档：
回答by Fabien Salles
Since PHP 5.6there is a better and cleanersolution for the original answer :
从PHP 5.6 开始，原始答案有一个更好、更清晰的解决方案：
With a multidimensional array like this :
使用这样的多维数组：
$a = array(array("Mac", "NT"), array("Irix", "Linux"))
We can use the splat operator:
我们可以使用splat 运算符：
return in_array("Irix", array_merge(...$a), true)
If you have string keys like this :
如果你有这样的字符串键：
$a = array("a" => array("Mac", "NT"), "b" => array("Irix", "Linux"))
You will have to use array_valuesin order to avoid the error Cannot unpack array with string keys:
您将不得不使用array_values以避免错误Cannot unpack array with string keys：
return in_array("Irix", array_merge(...array_values($a)), true)
