Syntax:
set datafile missing "<string>" show datafile missing unset datafile
Note: The treatment of certain cases has changed in this version of gnuplot. The example below shows the difference. Example:
set style data linespoints plot '-' title "(a)" 1 10 2 20 3 ? 4 40 5 50 e set datafile missing "?" plot '-' title "(b)" 1 10 2 20 3 ? 4 40 5 50 e plot '-' using 1:2 title "(c)" 1 10 2 20 3 NaN 4 40 5 50 e plot '-' using 1:($2) title "(d)" 1 10 2 20 3 NaN 4 40 5 50 e
Plot (a) differs because the third line contains only one valid number. Old gnuplot versions switched to a single-datum-on-a-line convention that the line number is "x" and the datum is "y", erroneously placing the point at(2,3).
Both the old and new gnuplot versions handle the same data correctly if the '?' character is designated as a marker for missing data (b).
Old gnuplot versions handled NaN differently depending of the form of the using clause, as shown in plots (c) and (d). Gnuplot now handles NaN the same whether the input column was specified as N or ($N). See also the
http://www.gnuplot.info/demo/mgr.htmlimageNaN demo.
Anton Gladky 2016-02-19