List Element

Format: x[ y ]

Arguments: [any] x Input list

[int] y Element number(s)

Returns: [any] The zero-based yth element(s) in the list x

Description: This operator is used to extract one or more elements from a list. Note that the first element in the list is x[0], not x[1]. If y is less than 0 or greater than the length of list x minus 1, null is returned.

If y contains a list of element numbers, a list of corresponding elements is returned. For example, x[2..4] returns the third, fourth, and fifth elements in x.

If x is a matrix (list of lists), you can extract particular elements by using this operator twice. For example, x[2][5] returns the element in column 3, row 6. You can also extract entire columns or rows. For example, x[2] returns the entire third column. Similarly, x[][5] returns the entire sixth row. To extract a range in a matrix, enter a range of values for the row and column numbers. x[2..3][3..5] returns all elements in columns 3 and 4 of rows 4, 5, and 6.

Note that x[y] and x#y are identical except that x[y] uses zero-based index numbers while x#y is one-based.

Examples: [11,12,13,14][0] = 11

[11,12,13,14][1..3] = [12,13,14]

["a","b","c"][2] = c

[[1,2],[3,4]][1] = [3,4]

[[1,2],[3,4]][1][0] = 3

x[count(x)-1] = last element in the list named x

See Also: Subscript, sublist, last, List Literal, Property