3.9.1 Horizontally arranged data files

Pyxplot also allows rows of data to be plotted against one another. To do so, the keyword rows is placed after the using modifier:

plot 'data.dat' index 1 using rows 1:2

For completeness, the syntax using columns is also accepted, specifying that columns should be plotted against one another, as happens by default:

plot 'data.dat' index 1 using columns 1:2

When plotting horizontally-arranged data files, the meanings of the index and every modifiers are altered slightly. The former continues to refer to vertically-displaced blocks of data separated by two blank lines. Blocks, as referenced in the every modifier, likewise continue to refer to vertically-displaced blocks of data points, separated by single blank lines. The row numbers passed to the using modifier are counted from the top of the current block.

However, the line numbers specified in the every modifier – i.e. variables $a$, $c$ and $e$ in the system introduced in the previous section – now refer to vertical column numbers. For example,

plot 'data.dat' using rows 1:2 every 2::3::9

would plot the data in row 2 against that in row 1, using only the values in every other column, between columns 3 and 9.