CODEWITHSUNDEEP
phparraysunset
Kiki
Kiki

Reputation: 333

PHP: unset from array using if statement

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?

Upvotes: 8

Views: 2589

Answers (7)

DixitNatasha
DixitNatasha

Reputation: 11

use This:

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

$fruit_num = count($fruits);
for ($i = 0 ; $i < $fruit_num; $i++){

    if ($fruits[$i] == 'apple' || $fruits[$i] == 'orange' || $fruits[$i] == 'melon' || $fruits[$i] == 'banana'){
        unset($fruits[$i]);
    }

}
print_r($fruits);

instead of :

$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);

Output :

Array ( [4] => pineapple )

Upvotes: 1

dWinder
dWinder

Reputation: 11642

Because after removing the first 3 element the $i value is 3 but the count of the array is 2 so the for loop breaks - remember the loop condition is re-evaluating in each iteration. Change to this will give you the desire output:

$size = count($fruits)
for ($i = 0 ; $i < $size; $i++){

Generally, using unset with for loop with int index is not recommended

Upvotes: 11

Vikal Singh
Vikal Singh

Reputation: 84

Problem is here count($fruits), because every loop cycle array going small.

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

Hope this will help!

Upvotes: 1

Qirel
Qirel

Reputation: 26460

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);

Upvotes: 16

MjM
MjM

Reputation: 581

I would recommend you to use foreach instead of for loop. Try the following code below.

<?php
$fruitss = ['apple', 'orange', 'melon', 'banana', 'pineapple','h'];

foreach ($fruitss as $key=>$fruits) {
    //echo $fruits;
    if ($fruits == 'apple' || $fruits == 'orange' || $fruits == 'melon' || $fruits == 'banana') {
        unset($fruitss[$key]);
    }
}
print_r($fruitss);
?>

Upvotes: 4

Pupil
Pupil

Reputation: 23958

There are many possible ways to do this in PHP as PHP is very rich with array and string functions.

In this answer, two approaches are discussed.

Basically, you want to remove the elements from array.

So, take another array with the elements you want to remove.

Find out the difference between your array and the new array.

Difference will definitely your expected result.

You can use array_diff()

Beauty of this approach is:

You can do it minimal lines of code, also, no loops required.

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];
$remove = ['apple', 'orange', 'melon', 'banana'];
$test = array_diff($fruits, $remove);
echo '<pre>';print_r($test);echo '</pre>';

Output:

Array
(
    [4] => pineapple
)

Or even using array_interset()

Take a temporary array with the only element(s) you want to maintain in your array.

Get array intersecting element.

You will have all other elements removed.

$fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];
$two = ['pineapple'];
$test2 = array_intersect($fruits, $two);
echo '<pre>';print_r($test2);echo '</pre>';

Output:

Array
(
    [4] => pineapple
)

Upvotes: 2

Hasitha Amarathunga
Hasitha Amarathunga

Reputation: 2005

I think problem is $i<count($fruits). It reduce the array size. So it's runs only 3 times. SO assign the array size to variable first.

<?php 

    $fruits = ['apple', 'orange', 'melon', 'banana', 'pineapple'];
    $n=count($fruits);
    for ($i = 0 ; $i <$n ; $i++){ 

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

?>

Upvotes: 4

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