Moving Array Element to Top in PHP

Moving array element to top in PHP

You can achieve that this way:

$arr = array(
    'a1'=>'1',
    'a2'=>'2'
);

end($arr);

$last_key     = key($arr);
$last_value   = array_pop($arr);
$arr          = array_merge(array($last_key => $last_value), $arr);

/*
    print_r($arr);

    will output (this is tested):
    Array ( [a2] => 2 [a1] => 1 )
*/

PHP: Move associative array element to beginning of array

You can use the array union operator (+) to join the original array to a new associative array using the known key (one).

$myArray = array('one' => $myArray['one']) + $myArray;
// or      ['one' => $myArray['one']] + $myArray;

Array keys are unique, so it would be impossible for it to exist in two locations.

See further at the doc on Array Operators:

The + operator returns the right-hand array appended to the left-hand array; for keys that exist in both arrays, the elements from the left-hand array will be used, and the matching elements from the right-hand array will be ignored.

Move array item with certain key to the first position in an array, PHP

No need to unset keys. To keep it short just do as follow

//appending $new in our array 
array_unshift($arr, $new);
//now make it unique.
$final = array_unique($arr);

Demo

How to move array elements to top if compared with string?

Use usort():

 function sortx($a, $b) {
    if(strpos($a['p_title'],'Apple ipad')!==false){
        return -1;
    }
    return 1;
}

usort($array, 'sortx');

Whenever the preceding value will contain this string, it will be pushed towards the beginning of the array.

If you want to use variable in usort() function, you need to use objects:

class SortTitles{
    public $string;
    function sortx($a, $b) {
        if(strpos($a['p_title'],$this->string)!==false){
            return -1;
        }
        return 1;
    }
    public function sort_titles($array){
        usort($array, 'self::sortx');
        return $array;
    }

}
$sort = new SortTitles;
$sort->string = 'Apple ipad';
$array = $sort->sort_titles($array);

Move array element with a particular value to top of array

This should work:

usort($data, function ($a, $b) {
    if ($a->Name != "House" && $b->Name == "House") {
        return 1;
    } elseif ($a->Name == "House" && $b->Name != "House") {
        return -1;
    } else {
        return $b->Total - $a->Total;
    }
});

From PHP: usort - Manual:

The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

In this case, return 1 tells the sorting function that House is greater than any other value, and -1 that House is lesser than any other value.

Move an array element to a new index in PHP

As commented, 2x array_splice, there even is no need to renumber:

$array = [
    0 => 'a', 
    1 => 'c', 
    2 => 'd', 
    3 => 'b', 
    4 => 'e',
];

function moveElement(&$array, $a, $b) {
    $out = array_splice($array, $a, 1);
    array_splice($array, $b, 0, $out);
}

moveElement($array, 3, 1);

redzarf comments: "To clarify $a is $fromIndex and $b is $toIndex"

Result:

[
    0 => 'a',
    1 => 'b',
    2 => 'c',
    3 => 'd',
    4 => 'e',
];

Move array element by associative key to the beginning of an array

This seems, funny, to me. But here ya go:

$test = array(
    'bla' => 123,
    'bla2' => 1234,
    'bla3' => 12345
);

//store value of key we want to move
$tmp = $test['bla2'];

//now remove this from the original array
unset($test['bla2']);

//then create a new array with the requested index at the beginning
$new = array_merge(array('bla2' => $tmp), $test);

print_r($new);

Output looks like:

Array
(
    [bla2] => 1234
    [bla] => 123
    [bla3] => 12345
)

You could turn this into a simple function that takes-in a key and an array, then outputs the newly sorted array.

UPDATE

I'm not sure why I didn't default to using uksort, but you can do this a bit cleaner:

$test = array(
    'bla' => 123,
    'bla2' => 1234,
    'bla3' => 12345
);

//create a function to handle sorting by keys
function sortStuff($a, $b) {
    if ($a === 'bla2') {
        return -1;
    }
    return 1;
}

//sort by keys using user-defined function
uksort($test, 'sortStuff');

print_r($test);

This returns the same output as the code above.

how to move to the top an array element

For this line,

unset($rows[$row]);  // error line

you need to unset the key in $rows and not $row itself which is a value in the foreach loop.

So, for unsetting it would look like:

<?php

foreach($rows as $key => $row){
    if($row['id'] == $_GET['id']){
        unset($rows[$key]); 
        // code line to move to the top 
        break;
    }
}

Don't use $rows = $row + $rows; kind of syntax as it makes it difficult to read during code reviews.

For a shorter syntax, you can use array_filter to filter out the row and then perform a swap taking the help of symmetric-array-destructuring.

Snippet:

<?php

$row = array_filter($rows, fn($arr) => $arr['id'] == $testID);
[$rows[array_keys($row)[0]], $rows[0]] = [$rows[0], $rows[array_keys($row)[0]]];

Online Demo

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