PHP slice range by keys not by index

Question

I have an array that looks like below:

$array = [
  1000 => 'something',
  2000 => 'something',
  10000 => 'something',
  20000 => 'something',
  300000 => 'something',
];

Let's say I want to get an interval between 2000 and 20000. Do I need to loop or is there a better way?

It's not an index so I can't use slice in this case.

What I'm hoping for

I could do this myself with a loop, but hopefully there is something more clever.

$range = getRange(2000, 20000, $array);
print_r($range);

Output

$range = [
  2000 => 'something',
  10000 => 'something',
  20000 => 'something',
];

Loop is the correct way to handle it. You can use any wrapper like array_filter as suggested but it loops too. So you can say using a wrapper is elegant but not cleverer. — nice_dev, Feb 03 '20 at 09:45

score 3 · Accepted Answer · answered Feb 03 '20 at 09:24

array_filter can filter based on the value or the key …

function getRange($min, $max, $array) {
  return array_filter($array, function($key) use ($min, $max) {
    return $key >= $min && $key <= $max;
  }, ARRAY_FILTER_USE_KEY ); // flag to pass the key into the callback function
}

score 2 · Answer 2 · answered Feb 03 '20 at 09:22

2

function getRange($start,$end, $array){
  $dataArray= array();
  foreach($array as $key=>$value){

    if($key>=$start && $key<=$end){
       $dataArray[$key]= $value;
     }
  }
 return $dataArray; 
}

You will need to iterate over the array and do it manually. Even if there is any built-in function that will iterate over the result. In short, you will always need to go through the data set and you will always have a complexity of O(N).

answered Feb 03 '20 at 09:22

Danyal Sandeelo

12,196
10
47
78

1

I ended up using the solution from @04FS with array_filter. It requires no iteration, even if PHP makes the iteration internally. – Jens Törnell Feb 03 '20 at 09:47
no problem, `array_filter` performs iteration on the backend – Danyal Sandeelo Feb 03 '20 at 10:06

score 0 · Answer 3 · answered Feb 03 '20 at 09:24

0

array_splice is the solution for this. But the problem with array_splice are keys will never be preserved. Check this out for the solution array_splice preserving keys

answered Feb 03 '20 at 09:24

Jonel Zape

42
6

If you read documentation about `array_splice`, 4th parameter is not for boolean. – Jonel Zape Feb 03 '20 at 09:39
and even you put `true` in the 4th parameter, keys still will not preserved. I just tried. – Jonel Zape Feb 03 '20 at 09:41
There is no example (#3) in https://www.php.net/manual/en/function.array-splice.php – Jonel Zape Feb 03 '20 at 09:52
Ahhh I stand corrected. I was thinking of `array_slice`. With `array_slice` keys can be preserved with the 4th parameter. – GetSet Feb 03 '20 at 10:05
ohhh that's why :D – Jonel Zape Feb 03 '20 at 10:12

PHP slice range by keys not by index

What I'm hoping for

Output

3 Answers3