Removing Empty Elements from a PHP Array Using foreach and array_filter

Method 1: Using a loop (foreach example)

The basic syntax is:

foreach (array_expression as $value)

foreach (array_expression as $key => $value)

Example code that removes falsy values by unsetting them:

<?php

foreach($arr as $k => $v){

if(!$v)

unset($arr[$k]);

}

?>

This approach is easy for beginners but has higher time and memory complexity, so it is generally not recommended for large arrays.

Method 2: Using array_filter() function

Signature:

array_filter(array $array [, callable $callback [, int $flag = 0 ]]) : array

The function passes each array value to the optional callback; if the callback returns true , the value is kept, otherwise it is removed. The keys are preserved unless a flag changes this behavior.

Key parameters:

array : the array to be filtered.

callback : optional function that determines whether a value should stay. If omitted, all entries equal to FALSE are removed.

flag : determines how the callback receives arguments. ARRAY_FILTER_USE_KEY passes only the key, ARRAY_FILTER_USE_BOTH passes both key and value.

Example code:

<?php

$arr = array(

0 => 'hello',

1 => false,

2 => -1,

3 => null,

4 => ''

);

echo "<pre>";

var_dump(array_filter($arr));

?>

Running the script produces:

/*   array(2) {

[0]=> string(5) "hello"

[2]=> int(-1)

} */