matplotlib 不会在图例中写 approx LaTeX 字符?

2022-01-24 00:00:00 python matplotlib latex

问题描述

由于某种原因，我无法让 matplotlib 在图例中写下 approx LaTeX 符号.

For some reason I can't get matplotlib to write down the approx LaTeX symbol in a legend.

这是一个 MWE:

import matplotlib.pyplot as plt plt.scatter([0.5, 0.5], [0.5, 0.5], label='$U_{c} approx %0.1f$' % 22) #plt.scatter([0.5, 0.5], [0.5, 0.5], label='$U_{c} simeq %0.1f$' % 22) #plt.scatter([0.5, 0.5], [0.5, 0.5], label='$U_{c} sim %0.1f$' % 22) plt.legend(fancybox=True, loc='upper right', scatterpoints=1, fontsize=16) plt.show()

请注意，第一行不会显示 approx 字符或后面的值，但 simeq 和 sim 都可以正常工作.

Notice the first line will not show the approx character or the value after it but both simeq and sim work fine.

我刚刚在 matplotlib 的 Github 但我突然想到我可能做错了什么，所以我最好问一下.如果是，我会删除关闭它.

I've just opened a new issue in matplotlib's Github but it occurred to me that I might be doing something wrong so I better ask. If I am, I'll ~~delete~~ close it.

解决方案

尝试使用原始字符串文字:r'$U_{c} approx %0.1f$'.

Try using a raw string literal: r'$U_{c} approx %0.1f$'.

In [8]: plt.scatter([0.5, 0.5], [0.5, 0.5], label=r'$U_{c} approx %0.1f$'%22) Out[8]: <matplotlib.collections.PathCollection at 0x7f799249e550> In [9]: plt.legend(fancybox=True, loc='best') Out[9]: <matplotlib.legend.Legend at 0x7f79925e1550> In [10]: plt.show()

出现这种情况的原因如下:

The reason this is happening is as follows:

如果字符串文字前面没有 r，则字符串被解释器解释为:

Without the r infront of the string literal, the string is interpreted by the interpreter as:

'$U_{c}' + 'a' + '大约 22.0$'

'$U_{c} ' + 'a' + 'pprox 22.0$'

'a' 是 ASCII Bell 的特殊转义字符:BEL.

The 'a' is a special escaped character for the ASCII Bell: BEL.

为确保字符串中的反斜杠 () 不会产生奇怪的转义字符，请在前面添加 r.

To make sure backslashes () in the string aren't creating weird escaped characters, add the r out front.

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