Fill up array with missing elements

Question

I have an array which looks like this:

array:6 [▼
    0 => 2
    1 => 2
    2 => 2
    6 => 5
    10 => 3
    11 => 1
]

I would like to check for a range of numbers e.g. 0 to 11 if these keys exist in my array. If not I want to create the element with the missing key and give it the value 0.

So I would end up with an array like this:

array:6 [▼
   0 => 2
   1 => 2
   2 => 2
   3 => 0
   4 => 0
   5 => 0
   6 => 5
   7 => 0
   8 => 0
   9 => 0
   10 => 3
   11 => 1
]

I tried something like this:

$range = range(0,11);

foreach($myArray as $key => $value){
  if(!in_array($key, $range)){
    $myArray[$key] = 0;
  }
}

But I just get the same array as at the beginning of the question.

Do you need to fill the missing array keys to with value 0?? — Murad Hasan
– Murad Hasan, Commented May 10, 2016 at 11:17

Rizier123 · Accepted Answer · 2016-05-10 11:27:43Z

You can create an array with array_fill_keys() and pass it the amount of keys you want with range() and fill the array with 0's. After that you can replace all elements which you already have in your array with array_replace().

<?php

    $array = [2 => 3, 5 => 2, 11 => 7];

    $result = array_replace(array_fill_keys(range(0, 11), 0), $array);
    print_r($result);

?>

The problem with your code is that you only loop over the elements of your array. So if you have just 3 elements you will just loop over these 3 elements.

If you want to fix your current code you would have to loop over the $range and then check if the key, not the value, exists in your array and if yes use the value from it otherwise create the element with the value 0.

Fixed code:

$range = range(0,11);
$result = [];

foreach($range as $key){
    if(isset($array[$key]))
        $result[$key] = $array[$key];
    else
        $result[$key] = 0;
}

Parth Panchal · Accepted Answer · 2016-05-10 11:17:30Z

1

You can try following code if you have range of array key upto 11 only.

for($i=0; $i<=11;$i++){
    if(!array_key_exists($i,$array)){
      $array[$i] = 0;
    }
}

answered May 10, 2016 at 11:17

Parth Panchal

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3 Comments

ssnake Over a year ago

use max(array_keys($array)) instead 11 it will find max key in the array; and you don't need to check last item (11) because it always will be exists.

RJParikh Over a year ago

Using your method it will append all 0 keys at end.

Parth Panchal Over a year ago

try if(!isset($array[$i])) instead of if(!array_key_exists($i,$array))

RJParikh · Accepted Answer · 2016-05-10 11:27:25Z

0

Use below code.

1) Using key() we find last key number.

2) Using array_key_exists(key,array) check for key exist in array or not.

3) Fill it in new array.

$arr = array(
    0 => 2,
    1 => 2,
    2 => 2,
    6 => 5,
    10 => 3,
    11 => 1,
   );
end($arr);
$endKey = key($arr);

for($i=0;$i<$endKey;$i++)
{
    if(!array_key_exists($i, $arr))
    {
        $newarr[$i] = 0;
    }
    else
    {
        $newarr[$i] = $arr[$i];
    }
}

Output

Array
(
    [0] => 2
    [1] => 2
    [2] => 2
    [3] => 0
    [4] => 0
    [5] => 0
    [6] => 5
    [7] => 0
    [8] => 0
    [9] => 0
    [10] => 3
)

answered May 10, 2016 at 11:27

RJParikh

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1 Comment

RJParikh Over a year ago

why minus vote?. Its working i have checked and tested. @Marco

RomanPerekhrest · Accepted Answer · 2016-05-10 11:33:20Z

0

The solution using array_diff_key and array_fill functions:

// $arr is your initial array
$diff = array_diff_key(array_fill(0,12,0), $arr);
$result = $arr + $diff;
ksort($result);

print_r($result);

The output:

Array
(
    [0] => 2
    [1] => 2
    [2] => 2
    [3] => 0
    [4] => 0
    [5] => 0
    [6] => 5
    [7] => 0
    [8] => 0
    [9] => 0
    [10] => 3
    [11] => 1
)

answered May 10, 2016 at 11:33

RomanPerekhrest

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Comments

Murad Hasan · Accepted Answer · 2016-05-10 11:28:03Z

-1

You need to browse the whole array for set missing keys value 0. I make a function for doing this, Check if the index is missing then set 0.

$array = array('0' => 2, '1' => 2, '2' => 2, '6' => 5, '10' => 3, '11' => 1);
function cleanArray(&$array){
    end($array);
    $max = key($array); //Get the final key as max!
    for($i = 0; $i < $max; $i++){
        if(!isset($array[$i])){
            $array[$i] = 0;
        }
    }
}

cleanArray($array);
ksort($array);
print_r($array);

edited May 10, 2016 at 11:28

answered May 10, 2016 at 11:22

Murad Hasan

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