它可以通过函数我做了三个函数复制返回数组中重复的值。

第二个函数只返回那些在数组中不重复的值，第三个和完整的函数返回所有值，但不重复，如果任何值被重复，它将其转换为单个;

function duplicate($arr) {
    $duplicate;
    $count = array_count_values($arr);
    foreach($arr as $key => $value) {
        if ($count[$value] > 1) {
            $duplicate[$value] = $value;
        }
    }
    return $duplicate;
}
function single($arr) {
    $single;
    $count = array_count_values($arr);
    foreach($arr as $key => $value) {
        if ($count[$value] == 1) {
            $single[$value] = $value;
        }
    }
    return $single;
}
function full($arr, $arry) {
    $full = $arr + $arry;
    sort($full);
    return $full;
}

唯一对我有用的是:

$array = array_unique($array, SORT_REGULAR);

编辑:SORT_REGULAR与原始数组保持相同的顺序。

这个例子只是一个替代。

    <?php
    $numbers = [1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,65776567567,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1,1,3,4,5,6,2,5,7,1];
    $unique_numbers = [];
    
    foreach($numbers as $number)
    {
      if(!in_array($number,$unique_numbers)){
          $unique_numbers[] = $number;
      }
    }
    print(json_encode($unique_numbers)); //// Array is now 1,3,4,5,6,2,7, ....

<?php
$a=array("1"=>"302","2"=>"302","3"=>"276","4"=>"301","5"=>"302");
print_r(array_values(array_unique($a)));
?>//`output -> Array ( [0] => 302 [1] => 276 [2] => 301 )`

根据数组的大小，我发现

$array = array_values( array_flip( array_flip( $array ) ) );

可以比array_unique快。

我没有使用任何函数。

$arr = array("1", "2", "3", "4", "5", "4", "2", "1");

$len = count($arr);
for ($i = 0; $i < $len; $i++) {
  $temp = $arr[$i];
  $j = $i;
  for ($k = 0; $k < $len; $k++) {
    if ($k != $j) {
      if ($temp == $arr[$k]) {
        echo $temp."<br>";
        $arr[$k]=" ";
      }
    }
  }
}

for ($i = 0; $i < $len; $i++) {
  echo $arr[$i] . " <br><br>";
}