The addition operator (+) and the subtraction operator (-) make it possible to add or subtract Lists respectively. When using these operators data type conversion can take place, e.g.,
[1, 3, "January "] + [2, 5.0 j, 98] // -> [3, 3.0 + 5.0 j, "January 98"] [0.1, 0.5] + [-1, 2] // -> [-0.9, 2.5] [7.8, 5.9] - [-1.3, 2.7] // -> [9.1, 3.2]
Lists to be added or subtracted must have the same lengths and the same structure.
To select a specific element of a List the list subscripting operator ([]) can be used. The index number within the brackets must be an Integer.
The index of the first element of a List is 0.
If nested Lists are accessed the corresponding number of indices must be given to get a list element. If fewer indices are given a list will be returned. Some examples:
a1 = [1, 2, 3, 4, 5]; // List with 8 elements a2 = [[1, 2], [3, 4]]; // 2x2 matrix a3 = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]]; // 2x2x2 matrix a1[3] // -> 4 a1[5] // -> ERROR! Index out of range. a2[0][1] // -> 2 a3[1][0][1] // -> 6 a3[0][1] // -> [3, 4] a3[0][1][1][4] // -> ERROR! Too many indices.
Robert Klima 2003-02-06