4.3  Working with Arrays of Items

For convenience, ECLⁱPS^e has some features for facilitating working with arrays of items. Arrays can be of any dimension, and can be declared with the dim/2 predicate:

?- dim(M,[3,4]).
M = []([](_131, _132, _133, _134),
       [](_126, _127, _128, _129),
       [](_121, _122, _123, _124))
yes.

dim/2 can also be used to query the dimensions of an array:

?- dim(M,[3,4]), dim(M,D).
...
D = [3, 4]
yes.

To access a specific element of an array in an expression, specify the index list of the desired element, e.g.

?- M = []([](2, 3, 5),
          [](1, 4, 7)),  X is M[1, 2] + M[2, 3].
X = 10
M = []([](2, 3, 5), [](1, 4, 7))
yes.

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Arrays are just structures The functor is not important Declare or query array size with dim/2 Access elements in expressions by specifying their index list (e.g. A[7], M[2,3]) Indices start at 1

Figure 4.2: Array notation

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For further details see the Array Notation section of the User Manual.