2D array storage [closed] - php

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Why it is the best practice to store your message or results in the two dimensional array?
I grilled it a lot in my mind but failed to produce an exact answer
The answers which came up to me with lot of grilling are as following :-
To store 2 messages at one time
To have the facility to store large messages
To store the large number of messages
though I am not sure about any one of them I admit it that my problem is not that programming oriented!

Answer 1

It might be best to look at what the PHP docs have to say about arrays first:
An array in PHP is actually an ordered map. A map is a type that
associates values to keys. This type is optimized for several
different uses; it can be treated as an array, list (vector), hash
table (an implementation of a map), dictionary, collection, stack,
queue, and probably more. As array values can be other arrays, trees
and multidimensional arrays are also possible.
As you can see from that definition, php arrays are very flexible and cover a lot of use cases. The particular area you are asking about is the multidimensional(2D) PHP array style. Now take a look at how a creating a 2D array looks:
$blank2DArray = array(array());
It's fairly clear that what you have is simply an array of arrays, ie a 2d Array.
So where 2D arrays are useful are cases where you have data that goes beyond simple key => value usage. A simple example: You have some results from multiple race car drivers and their scores from a race course. Each driver has multiple pieces of information so you need more than just a single key => value stored for each driver. You could make an object with attributes to store with this kind of thing, but you could handle it very quickly and simply with a PHP 2D array like this:
$drivers = array();
$drivers[0] = array('driver_id' => 2, 'course_id' => 5 'score' => 61.6);
$drivers[1] = array('driver_id' => 3, 'course_id' => 4 'score' => 70.8);
$drivers[2] = array('driver_id' => 8, 'course_id' => 2 'score' => 76.8, 'winner' => 1);
Each driver and their data are represented by a new array and each is added with an index(this does not need to be numeric). Notice driver[2] has an attribute winner that the others do not have; this is allowed because PHP allows for jagged arrays, ie not all entries have to be the same size. You can easily access child elements of each array like this:
$drivers[0]['driver_id'] //prints 2
$drivers[1]['course_id'] //prints 4
$drivers[2]['score'] //prints 76.8
PHP arrays are excellent for solving a variety of problems and 2D arrays specifically allow for representing complex data far beyond simple key => value storage. For an in-depth look under the hood at PHP arrays check out this blog post: Link
So to answer your question it may not always be best practice to use a 2D array, it will depend on the problem you are trying to solve. PHP arrays are a swiss army knife and the 2D variety are excellent for solving problems where you need to store variable, complex data elements.

Answer 2

Your question is very broad so I'll cover the two possibilities that come to mind:
1 > You're looking for a way to have PHP access and use multidimensional arrays:
$sData[0] = array("Name" => "T-Rex", "Type" => "dinosaur");
$sData[1] = array("Name" => "Frog", "Type" => "amphibian");
$sData[2] = array("Name" => "Salamander", "Type" => "amphibian);
This will allow you to have multiple rows with multiple sub-rows worth of data inside of them. There's no limit (besides machine memory) as to how many rows deep you can go.
2 > You're trying to figure out how to store that information in the database. In which case you need two tables like such:
Table: types
Structure: id INT(8) autoincrement, typename VARCHAR(65)
Example Data: 0, dinosaur -- 1, amphibian
Table: animals
Structure: id INT(8) autoincrement, type_id INT(8), name VARCHAR(65)
Example Data: 0, 0, T-Rex -- 1, 1, Frog -- 2, 1, Salamander