I'm barely an intermediate level php programmer and was asked the other day by a novice guy what use arrays actually have when mysql is easy to use, and can store stuff on a permanent basis.

Granted, arrays can write and recall information from text files for example, but it still seems that storing information is just more convenient with mysql.

What would a practical application of a PHP array be? I know this may seem like a stupid question, but I've never had a need to use an array.

One use is reading data from the database into its own array. The array keys would presumably match the column field names.

It is easier, and more readable, to use an array in this manner rather than individual $table_field variables set up for them. For instance, try iterating through a result set (which is probably returned in an array to begin with) with a foreach( $results as $ result ) loop.

At any rate, arrays are used to hold the data that is returned from the database query. Where else would you put the results?

Arrays are also good for setting up temporary datasets before implementing into an actual database, or even using them outright for such a purpose. Lets say you have a limited amount of locations that you want to concentrate on with city, county, zipcode keys and there are only twenty or so results for that array. It is simpler to create a static array than going through a database.

Well, a db SELECT usually returns data in an array ... However, tell novice guy he's comparing apples and oranges and should keep quiet - he's comparing databased storage with a programming construct - not a valid comparison. What if you want to pass a lot of values to a function - use an array - any time when you need to reference a lot of values in a singular way - use an array. What if you want to carry out more exotic manipulations via multi-dimensional arrays? Tell NG to go read a basic programming algorithms text.

Originally Posted by PaulW

What if you want to pass a lot of values to a function - use an array - any time when you need to reference a lot of values in a singular way - use an array.

That is another good use. Something that more than one WordPress plugin developers should learn when it comes to storing their option values. I have seen time, and time again, where they store each option inividually rather than lumping them into one options array and writing to disk once. In this instance, it saves resources and takes less of a performance hit.

PHP array is the actually map, A map is a type to associates values to keys. This type is optimized for several different uses. Array uses list of vector, hash table, dictionary, collection, stack, queue and probablly

correct me if i'm wrong,

i think you are talking about string arrays.

well simplest difference of array with database is arrays are stored in heap.

Originally Posted by DmitryS

correct me if i'm wrong,

i think you are talking about string arrays.

well simplest difference of array with database is arrays are stored in heap.

Well Victor did an "almost quote" right out of the Php manual which says:

Arrays

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.