PHP: unset from array using if statement

Question

I'm trying to unset specific values using if statement. My code is

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];

for ($i = 0 ; $i < count($fruits); $i++){ 
    if ($fruits[$i] == 'apple' || $fruits[$i] == 'orange' || $fruits[$i] == 'melon' || $fruits[$i] == 'banana'){
        unset($fruits[$i]);
    }
 }
 print_r($fruits);

I'm expecting it to return

Array
(
  [4] => pineapple
)

But the result is

Array
(
  [3] => banana
  [4] => pineapple
)

Why isn't 'banana' unset from the array?

Answer 1

There are many ways to Rome, as they say..

Using foreach()

A cleaner approach would be to use foreach instead of for loops, and checking against an array using in_array() instead of individually checking all the fruits.

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];

foreach ($fruits as $key=>$fruit) {
    if (in_array($fruit, ['apple', 'orange', 'melon', 'banana'])) {
        unset($fruits[$key]);
    }
}
print_r($fruits);

Using array_filter()

A more "fancy" way would be a one-liner using array_filter(),

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];

$fruits = array_filter($fruits, function($fruit) {
    return !in_array($fruit, ['apple', 'orange', 'melon', 'banana']);
});
print_r($fruits);

Using array_diff()

Even simpler, use array_diff(), which finds all elements that exists in only one of the arrays (essentially removing the duplicates).

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];
$remove = ['apple', 'orange', 'melon', 'banana'];
$result = array_diff($fruits, $remove);

Using array_intersect()

There's also array_intersect, which is sort of the inverse of array_diff(). This would find elements that exists in both arrays, and return that.

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];
$find = ['pineapple'];
$result = array_intersect($fruits, $find); 

• Live demo using foreach()
• Live demo using array_filter()
• Live demo using array_diff()
• Live demo using array_intersect()
• PHP.net on in_array()
• PHP.net on array_diff()
• PHP.net on array_filter()
• PHP.net on array_intersect()
• PHP.net on foreach()