Check out array_slice() http://php.net/manual/en/function.array-slice.php

Last argument true is to preserve keys.

When you pass the offset as negative, it starts from the end. It's a nice trick to get last elements without counting the total.

$array = [
    "a" => 1,
    "b" => 2,
    "c" => 3,
];

$lastElementWithKey = array_slice($array, -1, 1, true);

print_r($lastElementWithKey);

Outputs:

Array
(
    [c] => 3
)

// first
$value = reset($arr);
$key = key($arr);

(in that order)

See reset()^{PHP Manual}, key()^{PHP Manual}.

unset(key]); # in case you want to remove it.

However array_pop()^{PHP Manual} is working with the last element:

// last
$value = end(key = key($arr);
unset(key]); # in case you want to remove it.

See end()^{PHP Manual}.

For the fun:

[$value, $key] = [reset(arr)]; // first
[$value, arr), key($arr)]; // last

(PHP 7.1+)

or

list($value, $key) = array(reset(arr)); // first
list($value, $key) = array(end(arr)); // last

(PHP 4.3+)

or

extract(array('value' => reset(arr))); // first
extract(array('value' => end(arr))); // last

(PHP 4.3+; Caution: extract() in use!)

or

// first
reset($arr);
list(value) = each($arr);


// last
end($arr);
list(value) = each($arr);

(Note: The each() function is deprecated since PHP 7.2.0 and gone since PHP 8.0.0)

or whatever style of play you like ;)

Dealing with empty arrays

It was missing so far to deal with empty arrays. So it's a need to check if there is a last (first) element and if not, set the $key to null (as null can not be an array key):

// first
for ($key = null, $value = null; false !== $_ = reset($arr);)
{
    $value = $_;
    unset(key = key($arr)]);
    break;
}
unset($_);

// last
for ($key = null, $value = null; false !== arr);)
{
    $value = $_;
    unset(key = key($arr)]);
    break;
}
unset($_);

This will give for a filled array like $arr = array('first' => '1st', 'last' => '2nd.');:

string(4) "2nd." # value
string(4) "last" # key
array(1) { # leftover array
  ["first"]=>
  string(3) "1st"
}

And an empty array:

bool(false) # value
NULL # key
array(0) { # leftover array
}

Afraid of using unset?

In case you don't trust unset() having the performance you need (of which I don't think it's really an issue, albeit I haven't run any metrics), you can use the native array_pop() implementation as well (but I really think that unset() as a language construct might be even faster):

// first
reset(key = key(value = array_pop($arr);


// last
end(key = key(value = array_pop($arr);

Try end

<?php

$fruits = array('apple', 'banana', 'cranberry');
echo end($fruits); // cranberry

?>

You can use array_values for that like as

$array = [
    0 => 'apple',
    1 => 'banana',
    2 => 'orange',
    3 => 'grapes'
];

unset($array[1]);

print_r(array_values($array));

You are looking for array_shift().

PHP Array Shift

$array_fill = array(array('AAA','BBB','-','DDDD'), array(111,222,'-',444));
function clean_now($var)
{
    return $var == '-'? false: true;    
}

function cleanme($var)
{
    return array_filter($var, "clean_now"); 
}

print_r(array_map("cleanme",$array_fill));

Since it's 2 dimensional array, I first use array_map to filter the array inside of each array, and array_filter to remove '-' from the array.

Try to copy my code then run it on your side. I added the variable value.

Use array_splice():

If you're trying to remove the last n elements, use the following function:

function array_pop_n(array $arr, $n) {
    return array_splice($arr, 0, -$n);
}

Demo

If you want to retrieve only the last n elements, then you can use the following function:

function array_pop_n(array $arr, $n) {
    array_splice($arr,0,-$n);
    return $arr;
}

Demo

The order of key values in an associative array don't matter. Therefore you don't need to array_push or array_unshift. The only thing you need to do is associate a key to the value you want (or vice-versa). So you would write the following to dynamically add values to the $params array.

$key = "my_id:2";
$value = "23";
$params[$key] = $value;

Yep, no shifting, or pushing... just add the $key between the square brackets and your all good.