Supposing you have 100 titles in your record collection, and you need to size the set of variables needed for your array. There is a special command for setting up this dimension.

The DIM command is used to dimension an array, and the variables in your record collection table could be set up with a first line like this:

DIM artist$(100), title$(100), year(100), price(100)

So, artist$, title, and so on, are the names of the arrays, while 100 is the size.

Each dimension in the table is held inside round brackets, and if there is more than one element in a dimension each number must be separated from the next by a comma.

DIM chessboard(8,8)

This command will define a two-dimensional array, i.e. a matrix. Element numbers in arrays always start from zero, so the first entry must be indexed using 0, while the last entry can be accessed using the size minus one:

artist$(0)="Cindy Lauper"
title$(0)="Girls Just Want To Have Fun"
year(0)=1983
price(0)=10
artist$(99)="David Bowie"
title$(99)="Space Oddity"
year(99)=1967
price(99)=8

To extract elements from any array, you could then add something like this to your example program:

PRINT title$(0): PRINT price(0)
PRINT title$(99): PRINT year(99): PRINT price(99)

It is possible to define the "type" of the elements of an array, which must be the same for all elements. The ugBASIC language allows you to define the type in three ways: implicitly, explicitly, and in full.

The implicit way occurs by calling the DIM instruction without indicating any type: in this case, ugBASIC will use the default type which is INT (signed 16-bit value).

DIM integers(42)

You can change the default type with the OPTION DEFAULT TYPE statement, and this change will be reflected in the next DIM statement.

DIM integers(42)
OPTION DEFAULT TYPE LONG
DIM longs(42)

The explicit way is to use, at the end of the array name, a symbol that indicates the type: the dollar sign ($) for strings, the percentage symbol (%) for integers, and so on. Note that once the type is defined in this way, it is not necessary to use the symbol to refer to the array, as the type is understood to be defined by the DIM, and cannot be changed at runtime.

DIM strings$(42)
DIM integers%(42)
integers(10)=21 : ' type is implicitly INT
strings(10)="test" : ' type is implicitly STRING

The complete way is to use the AS keyword, which allows you to specify the type of each element precisely and punctually.

DIM strings(42) AS STRING
DIM integers(42) AS INT

For arrays that are not "read-only", you can modify them during program execution, either punctually or massively. The simplest way is to use the ARRAY command to reinitialize the array, exactly as was done with the DIM command.

DIM integers(3,2) = #{ 10, 20, 30, 40, 50, 60 }
PRINT integers(1,0) : ' will print "30"
ARRAY integers = #{ 53, 21, 10, 00, 00, 00 }
PRINT integers(1,0) : ' will print "10"

Clearly, if you have two variables of the same type and size, you can copy one on the other.

DIM integers1(3,2)
DIM integers2(3,2)
integers2 = integers1

Alternatively, if you want to fill an array with the same value, for example to reset it to zero, you can use the FILL command.

DIM integers(3,2) = #{ 10, 20, 30, 40, 50, 60 }
PRINT integers(1,0) : ' will print "30"
FILL integers
PRINT integers(1,0) : ' will print "0"
FILL integers WITH 42
PRINT integers(1,0) : ' will print "42"