我在比较时遇到了困难\pgfmathresult pt = 1 pt。一个完整的示例，其中一种情况有效，第二种情况无效（均在 x 轴上）：
\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{pgfplots.groupplots}
\pgfplotsset{compat=1.14}
\begin{filecontents}{clock1.dat}
time signal
0 0
100 0
100 1
200 1
200 0
249 0
\end{filecontents}
\begin{filecontents}{clock2.dat}
time signal
99751 0
99800 0
99800 1
99900 1
99900 0
100000 0
\end{filecontents}
\begin{document}
\pgfplotsset{ every non boxed x axis/.style={} }
\begin{tikzpicture}
\begin{groupplot}[group style={group name=my fancy plots,
group size=2 by 1,
yticklabels at=edge left,
horizontal sep=10pt
},
xticklabel style = {font = \scriptsize},
width = \textwidth,
height = 0.5\textwidth,
ymin = -0.25, ymax = 1.25,
restrict x to domain = 0:1e5,
ytick = {-1, -2, ..., -5},
]
\nextgroupplot[xmin = 0, xmax = 250,
restrict x to domain = 0:250,
xtick = {0, 100, 200},
xticklabel={\pgfmathparse{round(\tick/100)}{\ifdim\pgfmathresult pt=1 pt $\tau$%
\else \ifdim\pgfmathresult pt=0 pt $0$%
\else $\pgfmathprintnumber[int detect]{\pgfmathresult}\tau$%
\fi\fi%
}%
},
axis y line* = left,
scale only axis = true,
axis x discontinuity = none,
width = 0.5\textwidth,
extra y tick style = {blue, tick align = outside, tick label style = {rotate = 90, anchor = south}, every tick/.append style={white}, },
extra y ticks = {0.5, 2.0},
extra y tick labels = {clock, another},
]
\addplot [blue, very thin, domain = 0:250] table [x = time, y = signal] {clock1.dat};
\nextgroupplot[xmin = 0.9975e5, xmax = 1e5,
restrict x to domain = 0.9975e5:1e5,
xtick={.998e5, .999e5, 1e5},
scale only axis = true,
scaled x ticks = manual:{}{\pgfmathmultiply{#1}{1e-2}},
xticklabel={\pgfmathparse{int(round(\tick-1e3))}
{\ifdim\pgfmathresult pt = 1 pt $\Delta-\tau$%
\else \ifdim\pgfmathresult pt = 0 pt $\Delta$%
\else $\Delta\pgfmathprintnumber[int detect]{\pgfmathresult}\tau$%
\fi\fi%
}%
},
axis y line* = right,
ytick = \empty,
width = 0.5\textwidth
]
\addplot [blue, very thin, domain = 0.9975e5:1e5] table [x = time, y = signal] {clock2.dat};
\end{groupplot}
\end{tikzpicture}
\end{document}
这里（pdfTeX，版本 3.14159265-2.6-1.40.18（TeX Live 2017）（预加载格式=pdflatex））结果如下所示：
在右侧，我更希望看到 x-ticks $\Delta-2\tau$、$\Delta-\tau$ 和 $\Delta$。也就是说，我的目的是去掉“1”。在左侧，这个技巧效果很好。如果我处理较小的数据（在 [-1600,1600] 范围内，不需要缩放），它也有效。但我需要处理巨大的数字，所以我以这种方式准备了示例。
您能提供建议吗？提前谢谢您！问候。
答案1
我认为，如果您考虑到第二幅图中的数字为负数，您的比较将能够很好地进行。尽管如此，由于您正在检查整数，我想说，\ifnum在这里，稍微不那么脆弱的比较是有利的。
\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{pgfplots.groupplots}
\pgfplotsset{compat=1.14}
\begin{filecontents}{clock1.dat}
time signal
0 0
100 0
100 1
200 1
200 0
249 0
\end{filecontents}
\begin{filecontents}{clock2.dat}
time signal
99751 0
99800 0
99800 1
99900 1
99900 0
100000 0
\end{filecontents}
\begin{document}
\pgfplotsset{ every non boxed x axis/.style={} }
\begin{tikzpicture}
\begin{groupplot}[group style={group name=my fancy plots,
group size=2 by 1,
yticklabels at=edge left,
horizontal sep=10pt
},
xticklabel style = {font = \scriptsize},
width = \textwidth,
height = 0.5\textwidth,
ymin = -0.25, ymax = 1.25,
restrict x to domain = 0:1e5,
ytick = {-1, -2, ..., -5},
]
\nextgroupplot[xmin = 0, xmax = 250,
restrict x to domain = 0:250,
xtick = {0, 100, 200},
xticklabel={\pgfmathparse{int(round(\tick/100))}{%
\ifnum\pgfmathresult=1
$\tau$%
\else
\ifnum\pgfmathresult=0
$0$%
\else
$\pgfmathprintnumber[int detect]{\pgfmathresult}\tau$%
\fi
\fi%
}%
},
axis y line* = left,
scale only axis = true,
axis x discontinuity = none,
width = 0.5\textwidth,
extra y tick style = {blue, tick align = outside, tick label style = {rotate = 90, anchor = south}, every tick/.append style={white}, },
extra y ticks = {0.5, 2.0},
extra y tick labels = {clock, another},
]
\addplot [blue, very thin, domain = 0:250] table [x = time, y = signal] {clock1.dat};
\nextgroupplot[xmin = 0.9975e5, xmax = 1e5,
restrict x to domain = 0.9975e5:1e5,
xtick={.998e5, .999e5, 1e5},
scale only axis = true,
scaled x ticks = manual:{}{\pgfmathmultiply{#1}{1e-2}},
xticklabel={%
\pgfmathparse{int(round(\tick-1e3))}
\ifnum\pgfmathresult=-1
$\Delta-\tau$%
\else
\ifnum\pgfmathresult=0
$\Delta$%
\else
$\Delta\pgfmathprintnumber[int detect]{\pgfmathresult}\tau$%
\fi
\fi%
}, axis y line* = right,
ytick = \empty,
width = 0.5\textwidth
]
\addplot [blue, very thin, domain = 0.9975e5:1e5] table [x = time, y = signal] {clock2.dat};
\end{groupplot}
\end{tikzpicture}
\end{document}
