A plain C-u prefix interprets the region between point and mark as a single number or formula rather than a vector. If point and mark are both in the leftmost column, the lines in between are parsed in their entirety. Otherwise, point and mark define the corners of a rectangle whose contents are parsed. Each line of the grabbed area becomes a row of the matrix. The result will actually be a vector of vectors, which Calc will treat as a matrix only if every row contains the same number of values.
Any text surrounding the bracketed portion on the line is ignored.
Otherwise, the entire line is interpreted as a row vector as if it were surrounded by square brackets. 5' , then grabbing with a prefix argument of 8 would correctly split the line into two error forms. The result of the command will be a vector of numbers, one for each column in the input data. For example, suppose we have a column of numbers in a file which we wish to sum. Since there is only one column, the result will be a vector of one number, the sum.