PHP searching multidimensional array for item

Question

I currently have an array set up like this:

$u_id= array(
    array(
        NUM=>'2770', DESC=>'description one'
    ), 

    array(
        NUM=>'33356', DESC=>'description two'
    ), 

    array(
        NUM=>'13576', DESC=>'description three'
    ),

    array(
        NUM=>'14141', DESC=>'description four'
    )
);

I need to be able to pass a number through this array as $num (corresponding to a NUM=>'' in the array), and store the corresponding DESC=>'' as a string. For example, searching for "2770" would return "description one".

What would be the best way to go about doing this?

I have found multidimensional arrays to be a hassle in the past and they tend to get a bit confusing. I would do what JacobM suggests if this is all you are storing in each array. — adamjmarkham
– adamjmarkham, Commented Jun 25, 2011 at 1:11

Jacob Mattison · Accepted Answer · 2011-06-25 01:14:13Z

4

Are you constrained to this array structure? Because a more efficient structure would be to just do

$u_id= array(
     '2770' => 'description one',
     '33356' => 'description two',
     '13576' => 'description three',
     '14141' => 'description four'
);

That is to say, you just assume that the key is the number and the value is the description, rather than naming them explicitly. Then the code to find the correct description is just $u_id[2770] (or whichever).

If that's not acceptable, you could also do

$u_id= array(
    '2770' => array(
        NUM=>'2770', DESC=>'description one'
    ), 

    '33356' => array(
        NUM=>'33356', DESC=>'description two'
    ), 

    '13576' => array(
        NUM=>'13576', DESC=>'description three'
    ),

    '14141' => array(
        NUM=>'14141', DESC=>'description four'
    )
);

That is, the number is also used as the key to find the correct pair. The code to find the correct description becomes $u_id[2770]["NUM"].

In either of these scenarios, finding a given description from the number is a single step. If you can't change the array structure, though, then you'd have to loop through the array to check (which could take as many steps as there are items in the array).

edited Jun 25, 2011 at 1:14

answered Jun 25, 2011 at 1:04

Jacob Mattison

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8 Comments

adamjmarkham Over a year ago

You make a good point. If you don't need any more elements just use an associative array where the NUM is associated with a DESC.

John Over a year ago

I can change the structure to the first example you gave, but how would I go about finding the description for any given number?

Christopher Armstrong Over a year ago

@John if you changed it to @JacobM 's first example, you a given description for $number would be echo $u_id[$number]['DESC'];

Jacob Mattison Over a year ago

Edited to add a usage example, but the idea is that the number you're searching for is your array key, so if you have $search_num='2770' you can just get $u_id[$search_num] and that's your description.

Jacob Mattison Over a year ago

Actually, @Christopher, if he's using my first example he wouldn't need ['DESC']. It would just be $u_id[$number].

|

Trey · Accepted Answer · 2011-06-25 01:01:56Z

2

foreach($arrays as $arr){
  if($arr['NUM']==$num){
    return $arr['DESC'];
  }
}

answered Jun 25, 2011 at 1:01

Trey

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1 Comment

Trey Over a year ago

no problem, but Jacob is right, if you have the option of restructuring your array you should:)

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