Two examples of removing duplicate data from arrays in PHP-PHP Tutorial-php.cn

Two examples of removing duplicate data from arrays in PHP

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Release： 2016-07-25 08:55:37

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/**
* Remove duplicate data from array
* by bbs.it-home.org
**/
$input = array("a" => "green","", "red","b" = > "green", "","blue", "red","c" => "witer","hello","witer");
//$result = array_unique($input); // Remove duplicate elements
$result = a_array_unique($input); //Leave only a single element
foreach($result as $aa)
{
echo $aa."
";
}
function multi_unique ($array) {
foreach ($array as $k=>$na)
$new[$k] = serialize($na);
$uniq = array_unique($new);
foreach($uniq as $ k=>$ser)
$new1[$k] = unserialize($ser);
return ($new1);
}
function a_array_unique($array)//written Better
{
$out = array();
foreach ($array as $key=>$value) {
if (!in_array($value, $out))
{
$out[$key] = $value;
}
}
return $out;
}
?>

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PHP’s own array_unique function only applies to one-dimensional arrays, not multi-dimensional arrays Applicable, here is a PHP two-dimensional array deduplication array_unique function.

Example:

/**
* PHP two-dimensional array to remove duplicate data
* by bbs.it-home.org
*/
function unique_arr($array2D,$stkeep=false,$ndformat=true)
{
// Determine whether to retain the first-level array key (one Level 2 array keys can be non-numeric)
if($stkeep) $stArr = array_keys($array2D);
// Determine whether to keep level 2 array keys (all level 2 array keys must be the same)
if($ndformat) $ndArr = array_keys(end($array2D));
//For dimensionality reduction, you can also use implode to convert a one-dimensional array into a string connected with commas
foreach ($array2D as $v){
$v = join(" ,",$v);
$temp[] = $v;
}
//Remove repeated strings, that is, repeated one-dimensional arrays
$temp = array_unique($temp);
//Remove the The opened array is reassembled
foreach ($temp as $k => $v)
{
if($stkeep) $k = $stArr[$k];
if($ndformat)
{
$tempArr = explode (",",$v);
foreach($tempArr as $ndkey => $ndval) $output[$k][$ndArr[$ndkey]] = $ndval;
}
else $output[$k ] = explode(",",$v);
}
return $output;
}

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Call example:

//Array deduplication
$array2D =
array('first'=>array('title'=>'1111','date'=>'2222' ),'second'=>array('title'=>'1111','date'=>'2222'),'third'=>array('title'=>'2222',' date'=>'3333'));
print_r($array2D);
print_r(unique_arr($array2D,true));

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