6. Ranges

A range consists of two cells, the start and end cells of the range, separated by a colon.

For example, A0:B9 (or A0:C1R9, or R0C0:R9C1, or C0R0:R9C1, etc.) specifies a range including rows 0 to 9 of columns A and B. The range start and end values do not have to be in increasing order; B9:A0, B0:A9, and A9:B0 all refer to the same group of cells as A0:B9, but correspond to different directions for traversing the range. For example the command copy a0:a9 b9:b0 would copy column b to a in reverse order.

By default, ranges are traversed byrows to improve cache performance, since elements in a row are adjacent in memory. That is, in pseudo-code:

  for row = start_row to end_row
    for col = start_col to end_col
      use cell[row,col]

The bycols option can be used globally or with various commands (copy, eval, fill, etc.) to cause evaluation by columns. That is, in pseudo-code:

  for col = start_col to end_col
    for row = start_row to end_row
      use cell[row,col]

Note that the starting row may be less than, equal to, or greater than the ending row. Same for columns. So a range may consist of a single cell, row, or column (a0:a0, a0:d0, a0:a4), cells in "increasing" order (a0:b4), or cells in "partial decreasing" order (a4:b0, b0:a4), or cells in "decreasing" order (b4:a0).

A range basically represents a list of cells, and is explicitly converted to a list when used as a numeric function argument.

A range consisting of a single cell may be specified using just that one cell, e.g. A0 as a range is the same as A0:A0.