It’s especially confusing because the behaviour appears only for a very specific case: (a) it only works for columns and not for rows, because the columns correspond to variables and the rows do not, ...It’s especially confusing because the behaviour appears only for a very specific case: (a) it only works for columns and not for rows, because the columns correspond to variables and the rows do not, and (b) it only applies to the “rows and columns” version of the square brackets, and not to the subset() function, 114 or to the “just columns” use of the square brackets (next section).
