为什么 `datatool` 在 Tikz 图形中使用时会失败

Question

考虑以下示例

\documentclass[varwidth=true, border=2pt]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{datatool}

\begin{filecontents*}[overwrite]{test.csv}
Actual,Class 1,Class 2,Class 3
Class 1,1480.0,0.0,125.0
Class 2,112.0,1303.0,180.0
Class 3,174.0,95.0,1331.0    
\end{filecontents*}

\DTLloaddb[keys={Actual,Class 1,Class 2,Class 3}]% <options>
{test}% <db name>
{test.csv}% <filename>

\newcommand{\fetchdata}[2]{\DTLfetch{test}{Actual}{Class #1}{Class #2}}

\pgfplotsset{compat=1.17}
\begin{document}

Hi \fetchdata{1}{1}

\begin{tikzpicture}
    \begin{axis}[
            colormap={bluewhite}{color=(white) rgb255=(90,96,191)},
            xlabel=Predicted,
            xlabel style={yshift=-30pt},
            ylabel=Actual,
            ylabel style={yshift=20pt},
            xticklabels={Class 1, Class 2, Class 3}, % changed
            xtick={0,...,2}, % changed
            xtick style={draw=none},
            yticklabels={Class 1, Class 2, Class 3}, % changed
            ytick={0,...,2}, % changed
            ytick style={draw=none},
            enlargelimits=false,
            colorbar,
            xticklabel style={
              rotate=00
            },
            nodes near coords={\pgfmathprintnumber\pgfplotspointmeta},
            nodes near coords style={
                yshift=-7pt
            },
        ]
        \addplot[
            matrix plot,
            mesh/cols=3, % changed
            point meta=explicit, draw=gray
        ] table [meta=C] {
            x y C
            0 0 0.5
            1 0 0.01809
            2 0 0.02366
            
            0 1 0.05839
            1 1 0.90109
            2 1 0.01290
            
            0 2 0.06525
            1 2 0.08082
            2 2 0.96344
        };
        
        % Add text in a specific position
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,0) {(1531)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,0) {(30)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,0) {(33)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,1) {(102)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,1) {(1494)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,1) {(18)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,2) {(114)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,2) {(134)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,2) {(1344)};
    \end{axis}
\end{tikzpicture}
\end{document}

这产生了

但是，如果我尝试将其放入环境\DTLfetch中tikzpicture，那就是：

\documentclass[varwidth=true, border=2pt]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{datatool}

\begin{filecontents*}[overwrite]{test.csv}
Actual,Class 1,Class 2,Class 3
Class 1,1480.0,0.0,125.0
Class 2,112.0,1303.0,180.0
Class 3,174.0,95.0,1331.0    
\end{filecontents*}

\DTLloaddb[keys={Actual,Class 1,Class 2,Class 3}]% <options>
{test}% <db name>
{test.csv}% <filename>

\newcommand{\fetchdata}[2]{\DTLfetch{test}{Actual}{Class #1}{Class #2}}

\pgfplotsset{compat=1.17}
\begin{document}

\begin{tikzpicture}
    \begin{axis}[
            colormap={bluewhite}{color=(white) rgb255=(90,96,191)},
            xlabel=Predicted,
            xlabel style={yshift=-30pt},
            ylabel=Actual,
            ylabel style={yshift=20pt},
            xticklabels={Class 1, Class 2, Class 3}, % changed
            xtick={0,...,2}, % changed
            xtick style={draw=none},
            yticklabels={Class 1, Class 2, Class 3}, % changed
            ytick={0,...,2}, % changed
            ytick style={draw=none},
            enlargelimits=false,
            colorbar,
            xticklabel style={
              rotate=00
            },
            nodes near coords={\pgfmathprintnumber\pgfplotspointmeta},
            nodes near coords style={
                yshift=-7pt
            },
        ]
        \addplot[
            matrix plot,
            mesh/cols=3, % changed
            point meta=explicit, draw=gray
        ] table [meta=C] {
            x y C
            0 0 0.5
            1 0 0.\fetchdata{1}{1}
            2 0 0.02366
            
            0 1 0.05839
            1 1 0.90109
            2 1 0.01290
            
            0 2 0.06525
            1 2 0.08082
            2 2 0.96344
        };
        
        % Add text in a specific position
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,0) {(1531)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,0) {(30)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,0) {(33)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,1) {(102)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,1) {(1494)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,1) {(18)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,2) {(114)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,2) {(134)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,2) {(1344)};
    \end{axis}
\end{tikzpicture}
\end{document}

我明白了

Undefined control sequence.
\edtlgetrowforvalue ...def \@dtl@dogetrowforvalueLaTeX
Undefined control sequence.
\edtlgetrowforvalue ...#3}}\@dtl@dogetrowforvalueLaTeX
Undefined control sequence.
\dtlgetentryfromrow ...3->\edef \@dtl@do@getentryLaTeX
Undefined control sequence.
\dtlgetentryfromrow ...\the #3}}\@dtl@do@getentryLaTeX
Undefined control sequence.
\DTLfetch ...olumnindex {#1}{#4}}\dtlcurrentvalueLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing control sequence inserted.
<inserted text>LaTeX
Undefined control sequence.
\dtlgetrowindex ...@ {#4}\edef \dtl@dogetrowindexLaTeX
Undefined control sequence.
\dtlgetrowindex ...he \toks@ }}\dtl@dogetrowindexLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...lse \dtlrownum =\dtl@rowidxLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...idx \relax \edef \dtldbnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Undefined control sequence.
\dtlgetrowforvalue ...csname \edef \@dtl@dogetrowLaTeX
Undefined control sequence.
\dtlgetrowforvalue ... {\the \toks@ }{\dtl@rowidxLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...dtl@rowidx }}\@dtl@dogetrowLaTeX
Extra }, or forgotten \endgroup.
\pgfmathresult ...romrow {\dtlcurrentvalue }{2}{}}LaTeX
Undefined control sequence.
\dtlgetrowindex ...he \toks@ }}\dtl@dogetrowindexLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...lse \dtlrownum =\dtl@rowidxLaTeX
Missing number, treated as zero.
<to be read again>LaTeX
Undefined control sequence.
\dtlgetrowforvalue ...m =\dtl@rowidx \relax \edefLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...idx \relax \edef \dtldbnameLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...me dtldb@#1\endcsname \edefLaTeX
Undefined control sequence.
\dtlgetrowforvalue ...csname \edef \@dtl@dogetrowLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing { inserted.
<to be read again>LaTeX
Undefined control sequence.
\dtlgetrowforvalue ...dtl@rowidx }}\@dtl@dogetrowLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Undefined control sequence.
\GenericError  ...LaTeX
Undefined control sequence.
\GenericError  ...LaTeX
Missing { inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing number, treated as zero.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
\CheckEncodingSubset ...:\f@family \endcsname \fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \else.
\CheckEncodingSubset ...dafter \@firstoftwo \elseLaTeX
Extra \fi.
<recently read> \fiLaTeX
Argument of \tc@subst has an extra }.
<inserted text>LaTeX
Paragraph ended before \tc@subst was complete.
<to be read again>LaTeX
Extra \fi.
\GenericError ...rstchoice@ \else 6\fi \endcsnameLaTeX
Extra \fi.
\?-cmd ...ndcsname {\TextSymbolUnavailable #1}\fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
\?-cmd ...endcsname \csname ?\string #1\endcsnameLaTeX
Extra \fi.
\?-cmd ...sname \csname ?\string #1\endcsname \fiLaTeX
Extra \else.
\?-cmd ...\string #1\expandafter \endcsname \elseLaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing number, treated as zero.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \else.
\CheckEncodingSubset ...name #2:?\endcsname \elseLaTeX
Extra \fi.
\CheckEncodingSubset ...e #2:\f@family \endcsnameLaTeX
Extra \fi.
\CheckEncodingSubset ...:\f@family \endcsname \fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \else.
\CheckEncodingSubset ...dafter \@firstoftwo \elseLaTeX
Extra \fi.
<recently read> \fiLaTeX
Argument of \tc@subst has an extra }.
<inserted text>LaTeX
Paragraph ended before \tc@subst was complete.
<to be read again>LaTeX
Extra \fi.
\GenericError ...rstchoice@ \else 6\fi \endcsnameLaTeX
Extra \fi.
\?-cmd ...ndcsname {\TextSymbolUnavailable #1}\fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
\?-cmd ...endcsname \csname ?\string #1\endcsnameLaTeX
Extra \fi.
\?-cmd ...sname \csname ?\string #1\endcsname \fiLaTeX
Extra \else.
\?-cmd ...\string #1\expandafter \endcsname \elseLaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing number, treated as zero.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \else.
\CheckEncodingSubset ...name #2:?\endcsname \elseLaTeX
Extra \fi.
\CheckEncodingSubset ...e #2:\f@family \endcsnameLaTeX
Extra \fi.
\CheckEncodingSubset ...:\f@family \endcsname \fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \else.
\CheckEncodingSubset ...dafter \@firstoftwo \elseLaTeX
Extra \fi.
<recently read> \fiLaTeX
Argument of \tc@subst has an extra }.
<inserted text>LaTeX
Paragraph ended before \tc@subst was complete.
<to be read again>LaTeX
Extra \fi.
\GenericError ...rstchoice@ \else 6\fi \endcsnameLaTeX
Extra \fi.
\?-cmd ...ndcsname {\TextSymbolUnavailable #1}\fiLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
\?-cmd ...endcsname \csname ?\string #1\endcsnameLaTeX
Extra \fi.
\?-cmd ...sname \csname ?\string #1\endcsname \fiLaTeX
Extra \else.
\?-cmd ...\string #1\expandafter \endcsname \elseLaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
Extra \fi.
<recently read> \endcsnameLaTeX
Missing \endcsname inserted.
<to be read again>LaTeX
 ==> Fatal error occurred, no output PDF file produced!
Transcript written on main.log.
Latexmk: Getting log file 'main.log'
Latexmk: Examining 'main.fls'
Latexmk: Examining 'main.log'
Latexmk: Summary of warnings from last run of *latex:LaTeX

这没有意义...为什么\DTLfetch不能在'tikz 图片中按预期工作？

Answer 1

事情并不那么简单，\DTLfetch因为这个宏不可扩展。但是你可以利用这个很好的答案扩展后将的输出存储\DTLfetch在另一个宏中。

此外，我猜你不希望输入的是0.1480.0，而只是0.1480，所以你可以创建一个宏，让你将返回值与一个因子相乘。例如像这样：

\documentclass[varwidth=true, border=2pt]{standalone}
\usepackage{pgfplots}
\usepackage{datatool}

\begin{filecontents*}[overwrite]{test.csv}
Actual,Class 1,Class 2,Class 3
Class 1,1480.0,0.0,125.0
Class 2,112.0,1303.0,180.0
Class 3,174.0,95.0,1331.0    
\end{filecontents*}

\DTLloaddb[keys={Actual,Class 1,Class 2,Class 3}]% <options>
{test}% <db name>
{test.csv}% <filename>

\newcommand{\fetchdata}[4][1]{%
    \DTLfetch{test}{Actual}{Class #3}{Class #4}%
    \edtlgetrowforvalue{test}{\dtlcolumnindex{test}{Actual}}{Class #3}%
    \dtlgetentryfromcurrentrow{\dtlcurrentvalue}{\dtlcolumnindex{test}{Class #4}}%
    \pgfmathsetmacro{#2}{#1*\dtlcurrentvalue}%
}

\pgfplotsset{compat=1.17}
\begin{document}

\begin{tikzpicture}
    \begin{axis}[
            colormap={bluewhite}{color=(white) rgb255=(90,96,191)},
            xlabel=Predicted,
            xlabel style={yshift=-30pt},
            ylabel=Actual,
            ylabel style={yshift=20pt},
            xticklabels={Class 1, Class 2, Class 3}, % changed
            xtick={0,...,2}, % changed
            xtick style={draw=none},
            yticklabels={Class 1, Class 2, Class 3}, % changed
            ytick={0,...,2}, % changed
            ytick style={draw=none},
            enlargelimits=false,
            colorbar,
            xticklabel style={
              rotate=00
            },
            nodes near coords={\pgfmathprintnumber\pgfplotspointmeta},
            nodes near coords style={
                yshift=-7pt
            },
        ]
        \fetchdata[0.001]{\myResult}{1}{1}
        \addplot[
            matrix plot,
            mesh/cols=3, % changed
            point meta=explicit, draw=gray
        ] table [meta=C] {
            x y C
            0 0 0.5
            1 0 \myResult
            2 0 0.02366
            
            0 1 0.05839
            1 1 0.90109
            2 1 0.01290
            
            0 2 0.06525
            1 2 0.08082
            2 2 0.96344
        };
        
        % Add text in a specific position
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,0) {(1531)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,0) {(30)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,0) {(33)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,1) {(102)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,1) {(1494)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,1) {(18)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:0,2) {(114)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:1,2) {(134)};
        \node[anchor=south, yshift={-20pt}] at (axis cs:2,2) {(1344)};
    \end{axis}
\end{tikzpicture}
\end{document}