PHP:检查多维数组中的重复值
声明:本页面是StackOverFlow热门问题的中英对照翻译,遵循CC BY-SA 4.0协议,如果您需要使用它,必须同样遵循CC BY-SA许可,注明原文地址和作者信息,同时你必须将它归于原作者(不是我):StackOverFlow
原文地址: http://stackoverflow.com/questions/4948946/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
PHP: Check for duplicate values in a multidimensional array
提问by Maldoror
I have this issue with multidimensional arrays.
我对多维数组有这个问题。
Given the following multidimensional array:
给定以下多维数组:
Array(
[0] => Array("a", "b", "c")
[1] => Array("x", "y", "z")
[2] => Array("a", "b", "c")
[3] => Array("a", "b", "c")
[4] => Array("a", "x", "z")
)
I want to check its values and find duplicates (i.e. keys 0, 2 and 3) leaving just one key - value pair deleting the others, resulting in somthing like this:
我想检查它的值并找到重复项(即键 0、2 和 3),只留下一个键 - 值对删除其他键,结果是这样的:
Array(
[0] => Array("a", "b", "c")
[1] => Array("x", "y", "z")
[2] => Array("a", "x", "z")
)
How can I do that??
我怎样才能做到这一点??
回答by Tim Cooper
This will remove duplicate items from your array using array_unique()
:
这将使用array_unique()
以下命令从数组中删除重复项:
$new_arr = array_unique($arr, SORT_REGULAR);
回答by JF Dion
You can simply do it using in_array()
你可以简单地使用 in_array()
$data = Array(
0 => Array("a", "b", "c"),
1 => Array("x", "y", "z"),
2 => Array("a", "b", "c"),
3 => Array("a", "b", "c"),
4 => Array("a", "x", "z"),
);
$final = array();
foreach ($data as $array) {
if(!in_array($array, $final)){
$final[] = $array;
}
}
which will get you something like
这会让你像
array(3) {
[0] => array(3) {
[0] => string(1) "a"
[1] => string(1) "b"
[2] => string(1) "c"
}
[1] => array(3) {
[0] => string(1) "x"
[1] => string(1) "y"
[2] => string(1) "z"
}
[2] => array(3) {
[0] => string(1) "a"
[1] => string(1) "x"
[2] => string(1) "z"
}
}
回答by Gediminas
You can go smart with serialization for comparison of arrays.
您可以通过序列化来智能地比较数组。
var_dump(makeUnique($data));
function makeUnique(array $data)
{
$serialized = array_map(create_function('$a', 'return serialize($a);'), $data);
$unique = array_unique($serialized);
return array_intersect_key($unique, $data);
}
Have fun
玩得开心
回答by Mrdexed
To check using array_unique on multidimensional arrays, you need to flatten it out like so, using implode.
要在多维数组上使用 array_unique 检查,您需要像这样使用内爆将其展平。
$c=count($array)
for($i=0;$i<$c;$i++)
{
$flattened=implode("~",$array[$i]);
$newarray[$i]=$flattened;
}
if(count(array_unique($newarray)
<count($newarray))
{
//returns true if $array contains duplicates
//can also use array_unique on $newarray
//to remove duplicates, then explode,
//to return to default state
}
Hope this is helpful, took sometime to get it.
希望这有帮助,花了一些时间才能得到它。
回答by Artefacto
$arr = ...;
$final = array();
sort($arr);
foreach ($arr as $el) {
if (!isset($prev) || $el !== $prev)
$final[] = $el
$prev = $el;
}
This is a more efficient1solution (log n + n instead of quadratic) but it relies on a total order between all the elements of the array, which you may not have (e.g. if the inner arrays have objects).
这是一个更有效的1解决方案(log n + n 而不是二次方),但它依赖于数组所有元素之间的总顺序,而您可能没有(例如,如果内部数组有对象)。
1More efficient than using in_array
. Turns out array_unique
actually uses this algorithm, so it has the same shortcomings.
1比使用更有效in_array
。事实证明array_unique
实际上使用了这个算法,所以它也有同样的缺点。