Skip row in pgfplots table based on third variable

Question

I have the below data. I'd like to graph it such that there is a line for all rows for which bias, the last column, is zero, and another line for all rows for which bias is one. I thought perhaps this could be done by skipping rows based on bias=0, then adding another \addplot that skips rows when bias=1.

However, from section 4.21 of the pgfplots manual, I only see that rows can be skipped based on the values of the plotted points, not on a third variable.

Is there a way to skip points based on the value of a third variable? Or is there perhaps a better way to do this, without changing the form of the input file?

Thanks.

\documentclass{article}
\usepackage{pgfplotstable}

\begin{document}

\begin{tikzpicture}
  \begin{axis}[
xlabel=Period,
ylabel=ATE]
\addplot table[x=period,y=b] {
period b se z pvalue ll ul es bias
-4 -13.068966 4.7957403 -2.7251195 .00642782 -22.468444 -3.6694872 -.50936721 0
-3 -13.576271 2.9311518 -4.6317189 3.626e-06 -19.321223 -7.8313192 -.44067295 0
-2 -14.932203 2.8516346 -5.2363664 1.638e-07 -20.521304 -9.3431023 -.51395893 0
-1 -14.754237 2.3839111 -6.1890887 6.051e-10 -19.426617 -10.081857 -.52921471 0
0 -13.177966 2.9938464 -4.4016841 .00001074 -19.045797 -7.310135 -.47328062 0
0 -.83020764 2.8927267 -.2869983 .77411362 -6.4998477 4.8394324 -.47328062 1
1 -10.341667 3.0767608 -3.3612189 .00077599 -16.372007 -4.3113263 -.39240307 0
1 -1.6596195 2.7877028 -.59533588 .55161898 -7.1234166 3.8041776 -.39240307 1
};
\end{axis}
\end{tikzpicture}

\end{document}

Answer 1

You can use x expr to select the x coordinates:

\documentclass{article}
\usepackage{pgfplotstable}
\pgfplotsset{compat=1.15}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
xlabel=Period,
ylabel=ATE]

\pgfplotstableread{
period b se z pvalue ll ul es bias
-4 -13.068966 4.7957403 -2.7251195 .00642782 -22.468444 -3.6694872 -.50936721 0
-3 -13.576271 2.9311518 -4.6317189 3.626e-06 -19.321223 -7.8313192 -.44067295 0
-2 -14.932203 2.8516346 -5.2363664 1.638e-07 -20.521304 -9.3431023 -.51395893 0
-1 -14.754237 2.3839111 -6.1890887 6.051e-10 -19.426617 -10.081857 -.52921471 0
0 -13.177966 2.9938464 -4.4016841 .00001074 -19.045797 -7.310135 -.47328062 0
0 -.83020764 2.8927267 -.2869983 .77411362 -6.4998477 4.8394324 -.47328062 1
1 -10.341667 3.0767608 -3.3612189 .00077599 -16.372007 -4.3113263 -.39240307 0
1 -1.6596195 2.7877028 -.59533588 .55161898 -7.1234166 3.8041776 -.39240307 1
}\datatable

\addplot
  table[x expr={\thisrow{bias}==1?nan:\thisrow{period}},y=b]\datatable;
\addplot
  table[x expr={\thisrow{bias}==0?nan:\thisrow{period}},y=b]\datatable;
\end{axis}
\end{tikzpicture}
\end{document}