Merge data from qualifying rows of a 2d array into a flat associative array

Question

I have a $_SESSION array which I filter/sanitize by keys inside of a loop. This produces a 2d array of qualifying data, but I want to reduce it to a flat associative array.

Theoretical input:

$_SESSION = [
    // ...some unwanted row
    'saved_query_something' => ['product_category' => 'for-women'],
    'saved_query_something_else' => ['brand' => '7-diamonds'],
    // ...some unwanted row
    'saved_query_blah' => ['size' => 12],
    'saved_query_blar' => ['color' => 882536],
];

This is my current code that doesn't correctly reduce the data structure while sanitizing.

foreach ($_SESSION as $k => $v) {
    if (strstr($k, 'saved_query_') == true) {
        $saved = array_merge($v);
    }
}

The desired result:

[
  'product_category' => 'for-women',
  'brand' => '7-diamonds',
  'size' => 12,
  'color' => 882536,
]

Baba · Accepted Answer · 2012-09-13 11:23:11Z

2

You can try using array_merge

$array0 = Array ( "product_category" => "for-women" );
$array1 = Array ( "brand" => "7-diamonds" ) ;
$array2 = Array ( "size" => "12" ) ;
$array3 = Array ( "color" => "882536" );

$array = array_merge($array0,$array1,$array2,$array3);

print_r($array);

Output

Array ( [product_category] => for-women [brand] => 7-diamonds [size] => 12 [color] => 882536 )

See Demo

* ----- Update ----- *

If you are looking through a session

$_SESSION = Array();
$_SESSION[0] = Array("product_category" => "for-women");
$_SESSION[1] = Array("brand" => "7-diamonds");
$_SESSION[2] = Array("size" => "12");
$_SESSION[3] = Array("color" => "882536");

$final = array();
foreach ( $_SESSION as $key => $value ) {
    $final = array_merge($final, $value);
}

print_r($final);

edited Sep 13, 2012 at 11:23

answered Sep 13, 2012 at 11:17

Baba

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1 Comment

Ahmed Fouad Over a year ago

Please see edited question. I am missing something. I need the merge /combine to be done when I am looping thru $_SESSION

Dan Barzilay · Accepted Answer · 2012-09-13 11:32:30Z

2

Use array_merge_recursive() :

$result = array_merge_recursive($ar1, $ar2 [, array $...]);

Example: http://codepad.viper-7.com/Yr0LTb

edited Sep 13, 2012 at 11:32

answered Sep 13, 2012 at 11:15

Dan Barzilay

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1 Comment

mickmackusa Over a year ago

Recursion is unnecessary for the asked question.

xdazz · Accepted Answer · 2012-09-13 11:13:43Z

1

Use array_merge instead.

$ret = array_merge($arr1, $arr2, $arr3);

With your code, you should do:

$saved = array_merge($saved, $v);

answered Sep 13, 2012 at 11:13

xdazz

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Comments

Simon · Accepted Answer · 2012-09-13 11:16:04Z

0

You should have a look at the array_merge() function in PHP: http://php.net/manual/en/function.array-merge.php

Simply use as follows:

$array1 = Array ( [product_category] => for-women );
$array2 = Array ( [brand] => 7-diamonds );
$array3 = Array ( [size] => 12 );
$array4 = Array ( [color] => 882536 );

$combined = array_merge($array1, $array2, $array3, $array4);

answered Sep 13, 2012 at 11:16

Simon

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Comments

mickmackusa · Accepted Answer · 2024-10-31 23:13:04Z

To filter your 2d session array by first level prefix and reduce the payload to a flat associative array (assuming no key collisions are possible), inside your loop's condition block, use the array union assignment operator (+=). This will push each row's associative element into the result array without creating unwanted depth. Even if your rows have more than one element, the result array will still be flat.

Code: (Demo)

$_SESSION = [
    'junk' => ['foo' => 'bar'],
    'saved_query_1' => ['product_category' => 'for-women'],
    'saved_query_2' => ['brand' => '7-diamonds'],
    'junk2' => ['not valuable' => 'rubbish'],
    'saved_query_number' => ['size' => 12],
    'saved_query_11' => ['color' => 882536],
];

$saved = [];
foreach($_SESSION as $k => $v) {
    if (str_starts_with($k, 'saved_query_')) {
        $saved += $v;
    }
}
var_export($saved);

Functional-style code can be used, but will be less performant. Demo

var_export(
    array_merge(
        ...array_values(
            array_filter(
                $_SESSION,
                fn($k) => str_starts_with($k, 'saved_query_'),
                ARRAY_FILTER_USE_KEY
            )
        )
    )
);

Output:

array (
  'product_category' => 'for-women',
  'brand' => '7-diamonds',
  'size' => 12,
  'color' => 882536,
)

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