Value from php array seems incorrect

Question

I am having an issue with understanding why my array containing 3 elements must be sliced into 2 parts each. I wish to access a number I'm pushing into the array only however it seems to print out the index rather than the 'key' value I pushed into it ($number).

I have a 2d array I'm pushing an ID and an integer into, and then sort it :

$array = [[]];
array_push($array, $doc[_id], $number);
array_multisort($array);

I then filter any empty elements:

$array = array_filter($array); //remove null elements

This all works as id expect however the array looks like this by this point:

 unrated.array(5) 
 { 
 [2]=> object(MongoId)#32 (1) 
 { ["$id"]=> string(24) "57b99696ce2350100b000029" } 

 [3]=> object(MongoId)#31 (1) 
 { ["$id"]=> string(24) "57b998ccce2350181700002b" } 

 [4]=> object(MongoId)#33 (1) 
 { ["$id"]=> string(24) "57b99a84ce2350100b00002b" } 

 [5]=> int(2) [6]=> int(3) 

 }

Again, this is fine however it means when I loop over the array using the code below it appears to be longer than 3 elements, as I have to slice from 0-6 instead of 0-3:

$array = array_slice($array, 0, 6, true); //only get 3 elements from array
foreach ($array as $key => $value) {
echo $key; //prints out values from 1-5 weirdly.... should just print the $number value
$id = $value->{'$id'};
}

What I am trying to achieve is to find the element in the array with the lowest possible value that was pushed earlier (array_push($array, $doc[_id], $number);) however because I cannot understand why the array is split into 6 rather than 3 parts its even more confusing.

Question in short : How do I access the $number pushed into the array and why is my array 6 seemingly 6 in size when it contains only 3 elements.

Any help would be appreciated, thanks.

What is it that you expected array_push($array, $doc[_id], $number) to do, exactly? Because what that is actually doing is pushing two values onto the end of the array. The value of $doc[_id] and the value of $number. Which, if you're doing that 3 times, would explain why you're seeing 6 elements in the array. — Sherif
– Sherif, Commented Aug 21, 2016 at 13:10
Well i just need a way to access both the ID and the $number in my loop, so i expected pushing the $number to the array and the ID and sorting it would result in the array being sorted by the $number value. But ultimately the main issue i need solved is how to access the $number value from the loop as sorting etc i can solve with more research if there is an issue with it. — D3181
– D3181, Commented Aug 21, 2016 at 13:12
Well, your expectations are wrong then, because both $number and id would be values in the array. As such sorting the array would mean sorting both values. What you need to do is assign the $number directly to the id key instead. — Sherif
– Sherif, Commented Aug 21, 2016 at 13:17

Sherif · Accepted Answer · 2016-08-21 13:14:37Z

2

To be clear, array_push simply pushes one or more values onto the end of an array. The first argument of array_push is the array you wish to push the value(s) to, and any subsequent argument is a list of values you wish to push. So what you're doing with array_push($array, $doc[_id], $number) is pushing two values ($doc[_id] and $number) to the end of the array $array. array_push will just use the next available index as the key when it adds those values to the array. It will not allow you to specify a key. This is the same thing as doing $array[] = $value.

To specify a key you must assign a value directly to the array key like so: $array[$key] = $value.

answered Aug 21, 2016 at 13:14

Sherif

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3 Comments

D3181 Over a year ago

Is there a way to push the ID to the array and set the $number as the index of the array at the same time?

Sherif Over a year ago

Yes, you just specify the $number as the key, which is the exact opposite of what I'm doing here $array[$id] = $number then becomes $array[$number] = $id. Keep in mind that an array key is unique in a PHP array. As such you cannot have more than one key of the same value. Please be sure to read the manual for more details on using arrays.

D3181 Over a year ago

Awesome, thanks so much i'll look into this further! very helpful.

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