php - 从数组中删除重复项

Question

我使用下面的代码行来遍历我的数据库中的一个表：

$items_thread = $connection -> fetch_all($sql);

如果我打印出数组：

print_r($items_thread);

我会得到这个：

Array
(
    [0] => Array
        (
            [RecipientID] => 3
            [RecipientScreenname] => Tom L
            [RecipientFirstname] => Thomas
            [RecipientEmail] => info@xx.com
        )

    [1] => Array
        (
            [RecipientID] => 3
            [RecipientScreenname] => Tom L
            [RecipientFirstname] => Thomas
            [RecipientEmail] => info@xx.com
        )

    [2] => Array
        (
            [RecipientID] => 1
            [RecipientScreenname] => Lau T
            [RecipientFirstname] => TK
            [RecipientEmail] => lau@xx.co.uk
        )

)

但我想摆脱数组中的重复项，所以我使用array_unique

print_r(array_unique($items_thread));

我得到下面的奇怪结果，这不是我正在寻找的：

Array
(
    [0] => Array
        (
            [RecipientID] => 3
            [RecipientScreenname] => Tom L
            [RecipientFirstname] => Thomas
            [RecipientEmail] => info@xx.com
        )

)

理想情况下，我认为它应该返回：

Array
(
    [0] => Array
        (
            [RecipientID] => 3
            [RecipientScreenname] => Tom L
            [RecipientFirstname] => Thomas
            [RecipientEmail] => info@xx.com
        )

    [1] => Array
        (
            [RecipientID] => 1
            [RecipientScreenname] => Lau T
            [RecipientFirstname] => TK
            [RecipientEmail] => lau@xx.co.uk
        )

)

我该怎么做才能让它正确？我是否使用了错误的 PHP 语法/默认函数？

score 67 · Accepted Answer

该array_unique功能将为您执行此操作。您只需要添加SORT_REGULAR标志：

$items_thread = array_unique($items_thread, SORT_REGULAR);

但是，正如bren建议的那样，如果可能，您应该在 SQL 中执行此操作。

score 7 · Accepted Answer

7

您最好过滤掉 SQL 查询中的重复项。添加一个获取唯一收件人 ID 的约束

于 2011-02-18T00:28:32.780 回答

score 4 · Accepted Answer

要删除重复值，我们可以使用array_unique()函数。它的功能是接受一个数组并返回另一个没有重复值的数组。

array_unique() 的一般描述如下：

General Format = array array_unique(array $array [, int $sort_flags=sort_string] )
Parameters     = array: Input array ->sort_flags:
    The second optional parameter is used to compare items as follows
         1. SORT_REGULAR - Normal
         2. SORT_NUMERIC - Numerically
         3. SORT_STRING - As
         4. string  SORT_LOCALE_STRING - As string, based on the current locale.
Return Value   = Another array without duplicate values

示例 1：

<?php
$array=array('cricket'=>11,'football'=>11,'chess'=>2);
echo"<br/><b>Initially the values of \$array is:</b><br/>";
var_dump($array);
echo"<br/><b>After removing the duplicates:</b><br/>";
print_r(array_unique($array));
?>

输出：

Initially the values of $array is:
array(3) {
  ["cricket"] => int(11)
  ["football"] => int(11)
  ["chess"] => int(2)
}

After removing the duplicates:
Array
(
    [cricket] => 11
    [chess] => 2
)

score 1 · Accepted Answer

尝试这个：

$data = array_map('unserialize', array_unique(array_map('serialize', $data)));

输出以下内容：

Array
(
    [0] => Array
        (
            [RecipientID] => 3
            [RecipientScreenname] => Tom L
            [RecipientFirstname] => Thomas
            [RecipientEmail] => info@xx.com
        )

    [2] => Array
        (
            [RecipientID] => 1
            [RecipientScreenname] => Lau T
            [RecipientFirstname] => TK
            [RecipientEmail] => lau@xx.co.uk
        )
)

但我也认为你应该在你的数据库中实现这个。另外，请查看我的其他答案和解决方案。

score 1 · Accepted Answer

您可以使用此代码，希望对您有所帮助。它完全有效：

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

for($i=0; $i<=count($array); $i++)
 {

    if($array[$i] != '')
    {
        for($j=$i+1; $j<=count($array); $j++ )
        {
            if($array[$i]==$array[$j])
            {
                $array[$j] = '';
            }
            else
            {
                $temp[$array[$i]]=$array[$i];
            }

         }

    }
}

print_r($temp);

score 0 · Accepted Answer

您可以使用常规的 php 数组来实现这一点。

$newArray = array();
foreach ($origArray as $user)
{
   $newArray[$user['RecipientID']] = $user;
}

score 0 · Accepted Answer

~~$unique = array_keys(array_flip($array));~~

~~它更快，而且它重置了数组键索引。~~

~~来源： http: //php.net/manual/en/function.array-unique.php#89519~~

这仅适用于简单的数组。

score 0 · Accepted Answer

请检查下面的代码，我希望这对您有帮助。

$resultArray = uniqueAssocArray($actualArray, 'RecipientID');

function uniqueAssocArray($array, $uniqueKey) {
if (!is_array($array)) {
    return array();
}
$uniqueKeys = array();
foreach ($array as $key => $item) {
    $groupBy=$item[$uniqueKey];
    if (isset( $uniqueKeys[$groupBy]))
    {
        //compare $item with $uniqueKeys[$groupBy] and decide if you 
        //want to use the new item
        $replace= false; 
    }
    else
    {
        $replace=true;
    }
    if ($replace) $uniqueKeys[$groupBy] = $item;   
}
return $uniqueKeys;

}

score 0 · Accepted Answer

$res1       = mysql_query("SELECT * FROM `luggage` where r_bus_no='".$tour_id."' and `date1`='$date' AND `login_id`='".$_SESSION['login_id']."'");
}
/// create a array to store value
$city_arr   = array();
if(mysql_num_rows($res1)>0)
{
    while($row1 = mysql_fetch_array($res1))
    {

/// insert the value in array use the array_push function
            array_push($city_arr,$row1['r_to']);
    }

//// remove the duplicate entry in array use the array_unique function
    $a          = array_unique($city_arr);
    echo "<option value='' selected='selected'> -- Select City ---</option>";
    foreach($a as $b)
    {
    ?>
    <option value="<?php echo $b ;?>"><?php echo city($b); ?></option>
    <?php       
    }
}

php - 从数组中删除重复项

9 回答 9

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