Remove/unset every other key in multidimensional array but preserve keys

Question

I have a long multidimensional array with timestamps as keys which contain arrays of values. Something like this but with more timestamps:

array(3) {
  [1502609400]=>
  array(2) {
    ["Item1"]=>
    array(1) {
      ["PRICE"]=>
      float(100)
    }
    ["Item2"]=>
    array(1) {
      ["PRICE"]=>
      float(50)
    }
  }
  [1502611200]=>
  array(2) {
    ["Item1"]=>
    array(1) {
      ["PRICE"]=>
      float(200)
    }
    ["Item2"]=>
    array(1) {
      ["PRICE"]=>
      float(150)
    }
  }
  [1502613000]=>
  array(2) {
    ["Item1"]=>
    array(1) {
      ["PRICE"]=>
      float(500)
    }
    ["Item2"]=>
    array(1) {
      ["PRICE"]=>
      float(250)
    }
  }

How can I remove every every second array of the array without losing the keys as timestamp? So I end up with this:

array(3) {
  [1502609400]=>
  array(2) {
    ["Item1"]=>
    array(1) {
      ["PRICE"]=>
      float(100)
    }
    ["Item2"]=>
    array(1) {
      ["PRICE"]=>
      float(50)
    }
  }
  [1502613000]=>
  array(2) {
    ["Item1"]=>
    array(1) {
      ["PRICE"]=>
      float(500)
    }
    ["Item2"]=>
    array(1) {
      ["PRICE"]=>
      float(250)
    }
  }

If I use a for loop and unset every second key I lose all the keys and end up with 0, 1, 2 etc. instead of the timestamp.

In a loop, just check for index, and unset every second element: — M_Idrees
– M_Idrees, Commented Aug 14, 2017 at 9:15

localheinz · Accepted Answer · 2017-08-14 09:54:22Z

4

In a loop, check for index and unset every second element:

You can use custom $index variable, like this:

$index = 0; // points to first element

foreach ($array as $key => $value) {
    if ($index % 2 != 0) { //check for un-even
        unset($array[$key]);
    }   

    $index++; // move pointer to next element
}

edited Aug 14, 2017 at 9:54

localheinz

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answered Aug 14, 2017 at 9:16

M_Idrees

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3 Comments

ubik Over a year ago

Thanks for the quick reply, but $key would be 1502611200 for example. So this wont work, since it's divisible by 2.

M_Idrees Over a year ago

Added custom $index variable to maintain it separately, only purpose to find-out the even/odd elements.

ubik Over a year ago

Just wanted to say that too, as I combined your answer and @Osama 's :) Thanks @M Idrees this works great! Marked as correct.

Osama · Accepted Answer · 2017-08-14 09:27:53Z

1

$i=1 // where the key to remove 
$x=0; //loop to determine the key position
foreach ($array as $key=>$value){
if($x==$i){
unset($array[$key]);
}
$x++;
}

answered Aug 14, 2017 at 9:27

Osama

3,0301 gold badge15 silver badges16 bronze badges

4 Comments

ubik Over a year ago

Thanks a lot! This works perfectly. Didn't think about adding a counter which makes a lot of sense. * Edit: Sorry, this does not work with a longer array. Did I misunderstand something?

localheinz Over a year ago

Why iterate over the entire array when all you want is modify the first element?

Osama Over a year ago

Depending on the same idea you can achieve that note the every second item must be 1,3,5,6 and the counter must be less than array count if you need help I can edit code or if you can do it by yourself

ubik Over a year ago

Thanks for the help, the count brought me up to the now correct answer by @M-Idrees.

Sarkouille · Accepted Answer · 2017-08-14 09:39:42Z

1

In that kind of case, a simple foreach can be more efficient perfwise than a standard function :

foreach ($array as $key => $val) {
    if (array_key_exists('Item2', $val)) {
        unset($val['Item2']);
    }
}

answered Aug 14, 2017 at 9:39

Sarkouille

1,2319 silver badges16 bronze badges

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