Select only unique array values from this array

问题

I have the following variable $rows:

Array (

[0] => stdClass Object
    (
        [product_sku] => PCH20
    )

[1] => stdClass Object
    (
        [product_sku] => PCH20
    )

[2] => stdClass Object
    (
        [product_sku] => PCH19
    )

[3] => stdClass Object
    (
        [product_sku] => PCH19
    )

)

I need to create second array $second containing only unique values:

Array (

[0] => stdClass Object
    (
        [product_sku] => PCH20
    )

[1] => stdClass Object
    (
        [product_sku] => PCH19
    )

)

But when i run array_unique on $rows, i receive:

Catchable fatal error: Object of class stdClass could not be converted to string on line 191

回答1:

$uniques = array();
foreach ($array as $obj) {
    $uniques[$obj->product_sku] = $obj;
}

var_dump($uniques);

回答2:

array_unique()

The optional second parameter sort_flags may be used to modify the sorting behavior using these values:

Sorting type flags:

SORT_REGULAR - compare items normally (don't change types)

SORT_NUMERIC - compare items numerically

SORT_STRING - compare items as strings

SORT_LOCALE_STRING - compare items as strings, based on the current locale.

Also note the changenotes below

5.2.10 Changed the default value of sort_flags back to SORT_STRING.

5.2.9 Added the optional sort_flags defaulting to SORT_REGULAR. Prior to 5.2.9, this function used to sort the array with SORT_STRING internally.

$values = array_unique($values, SORT_REGULAR);

回答3:

The default behavior of function array_unique() is to treat the values inside as strings first. So what's happening is that PHP is attempting to turn your objects into strings (which is throwing the error).

You can modify your function call like this:

$uniqueArray = array_unique($rows, SORT_REGULAR);

This will compare values without changing their data type.

回答4:

Please check below code, I hope this will be helpful to you.

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

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;
}

来源：https://stackoverflow.com/questions/11340450/select-only-unique-array-values-from-this-array

标签

php

arrays

array-unique