# Tikz: place node leftmost of two nodes of different widths

I have the following tikz picture:

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\coordinate (origin) at (0,0) ;
\node[above=10pt of origin,anchor=east] (topnode) {Short};
\node[below=10pt of origin,anchor=east] (bottomnode) {Longer Node};
\end{tikzpicture}
\end{document}


My goal is to place a node at position (x,y), with y=0, but with x equal to leftmost of the two nodes (topnode) and (bottomnode). I would like to do this without hard-coding the position. So that the position would still be correct if I changed the content of those two nodes.

A local bounding box known the left/right/top/bottom-most coordinate of everything that's inside.

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\coordinate (origin) at (0,0) ;
\begin{scope}[local bounding box=nodes]
\node[above=10pt of origin,anchor=east] (topnode) {Short};
\node[below=10pt of origin,anchor=east] (bottomnode) {Longer Node};
\end{scope}
\node[anchor=west] at (origin-|nodes.west) {here I am};
\end{tikzpicture}
\end{document}


A different way: use the \pgfgetlastxy:

\documentclass[tikz]{standalone}
\usetikzlibrary{positioning}
\newdimen\xone
\newdimen\y
\newdimen\xtwo
\begin{document}
\begin{tikzpicture}
\coordinate (origin) at (0,0) ;
\node[above=10pt of origin,anchor=east,inner sep=0pt] (topnode) {Short};
\node[below=10pt of origin,anchor=east,inner sep=0pt] (bottomnode) {Longer Node};
\path (topnode.west);
\pgfgetlastxy{\xone}{\y};
\path (bottomnode.west);
\pgfgetlastxy{\xtwo}{\y};
\draw ({min(\xone,\xtwo)},0) circle (1pt);
\end{tikzpicture}
\end{document}


I put a circle to the desired place. You can change it to whatever you want, you can even use this as a coordinate: