我想通过函数和从特定列表获取最大/最小值\findmax
,\findmin
以便在ymin
和中使用它ymax
。我真的不明白\pgfplotstablesort
函数是如何工作的。最完美的是调用\findmax{YAmax,YA,YAmin}
并返回这 3 列的最大值。
\documentclass{standalone}
\usepackage{pgfplots}
\usepackage{pgfplotstable}
\usepackage{filecontents}
\newcommand{\findmax}[1]{
\pgfplotstablesort[sort key={#1},sort cmp={float >}]{\sorted}{data.dat}%
\pgfplotstablegetelem{0}{1}\of{\sorted}%
\let\ymax=\pgfplotsretval%
}
\begin{filecontents}{data.dat}
X YA YAmin YAmax YB YBmin YBmax
1 5 4 6 6 5 7
2 3 2 5 7 5 9
3 6 1 9 9 7 13
4 4 2 6 6 1 11
5 0 -1 3 3 0 5
6 1 -3 6 1 -1 2
\end{filecontents}
\begin{document}
\pgfplotsset{width=3cm,scale only axis}
\begin{tikzpicture}
%\findmax{YAmax,YA,YAmin}
%\findmin{YAmin,YA,YAmin}
\begin{axis}[at={(0,0)},title=YA]%,ymin=\ymin,ymax=\ymax]
\addplot [very thick,smooth,red,solid] table [x=X, y=YA] {data.dat};
\addplot [very thick,smooth,red,dotted] table [x=X, y=YAmin] {data.dat};
\addplot [very thick,smooth,red,dotted] table [x=X, y=YAmax] {data.dat};
\end{axis}
%\findmax{YBmax,YB,YBmin}
%\findmin{YBmax,YB,YBmin}
\begin{axis}[at={(4cm,0)},title=YB]%,ymin=\ymin,ymax=\ymax]
\addplot [very thick,smooth,red,solid] table [x=X, y=YB] {data.dat};
\addplot [very thick,smooth,red,dotted] table [x=X, y=YBmin] {data.dat};
\addplot [very thick,smooth,red,dotted] table [x=X, y=YBmax] {data.dat};
\end{axis}
\end{tikzpicture}
\end{document}
答案1
终于完成了。
刚刚创建了一个函数来查找外部表中所选列的极值。
\newcommand{\findmax}[1]{
% Starting value for max : 0
\pgfmathtruncatemacro{\mymax}{0}
% Parsing each element of the first column
\pgfplotsinvokeforeach {0,...,5}{
\pgfplotstablegetelem{##1}{#1}\of{\mytable}
\ifthenelse{ \pgfplotsretval >\mymax }
{\pgfmathtruncatemacro{\mymax}{\pgfplotsretval}} % valid
{} %invalid
}
\let\ymax=\mymax%
}
答案2
和\pgfplotstablesort
:
\begin{filecontents}[overwrite]{data.dat}
X YA YAmin YAmax YB YBmin YBmax
1 5 4 6 6 5 7
2 3 2 5 7 5 9
3 6 1 9 9 7 13
4 4 2 6 6 1 11
5 0 -1 3 3 0 5
6 1 -3 6 1 -1 2
\end{filecontents}
\documentclass[border=5mm, varwidth]{standalone}
\usepackage{pgfplots}
\usepackage{pgfplotstable}
% \pgfplotsset{width=3cm,scale only axis}
\usepackage{amsmath}
\begin{document}
\pgfplotstableread[]{data.dat}{\mytable}
\pgfplotstablegetrowsof{\mytable}
\pgfmathtruncatemacro\LastRowNo{\pgfplotsretval-1}
\pgfplotstabletypeset[]{\mytable}
%\pgfplotstablesort[sort key={YA}]{\sorted}{\mytable}
%\pgfplotstabletypeset[]{\sorted}
\newcommand{\findYmax}[1]{%
\pgfplotstablesort[sort key={#1}]{\sorted}{\mytable}%
\pgfplotstablegetelem{\LastRowNo}{#1}\of{\sorted}%
\xdef\tempYmax{\pgfplotsretval}}
\newcommand{\findXmax}[1]{%
\pgfplotstablesort[sort key={#1}]{\sorted}{\mytable}%
\pgfplotstablegetelem{\LastRowNo}{X}\of{\sorted}%
\xdef\tempXmax{\pgfplotsretval}}
\findXmax{YB}
\findYmax{YB}
$YB_{\max}=\tempYmax$ at $X_{\max}=\tempXmax.$
\begin{tikzpicture}
%\findmax{YAmax,YA,YAmin}
%\findmin{YAmin,YA,YAmin}
\begin{axis}[at={(0,0)},title=YA]%,ymin=\ymin,ymax=\ymax]
\addplot[very thick,smooth,red,solid] table [x=X, y=YA]{data.dat} node[above]{YA};
\findXmax{YA}
\findYmax{YA}
\addplot[mark=*, blue] coordinates{(\tempXmax,\tempYmax)} node[above]{$(X_{\max}, YA_{\max}) = (\tempXmax,\tempYmax) $};
\end{axis}
\end{tikzpicture}
\end{document}