设置“ matplotlib.rcParams ['text.usetex'] = True”以在标签中使用LaTeX并使用德语语言环境使用逗号时的Python图形问题

Question

我想创建其中x和y刻度标签显示其数字值的格式，这些数字值已正确设置为德语格式，即使用逗号作为小数点分隔符。我也想使用LaTeX元素在x或y轴标签或图例中。以下代码显示第一个图形是根据英语版本创建的。

# -*- coding: utf-8 -*-
import numpy as np
import matplotlib
import matplotlib.pyplot as plt

import locale

#  Set to German locale to get comma decimal separater
locale.setlocale(locale.LC_NUMERIC, "deu_deu")

# Use LaTeX elements
matplotlib.rcParams['text.usetex'] = True

t = np.linspace(0.0, 1.0, 100)
s = t*np.cos(4 * np.pi * t) + 2

fig, ax = plt.subplots(figsize=(6, 4))
ax.plot(t, s)

ax.set_xlabel(r'Time $t$ with $t \le 1$')
ax.set_ylabel('Velocity $v(t)$')

plt.show()

fig.savefig("Mein_Test1.pdf")


fig2, ax2 = plt.subplots(figsize=(6, 4))
ax2.plot(t, s)

ax2.set_xlabel(r'Time $t$ with $t \le 1$')
ax2.set_ylabel('Velocity $v(t)$')

plt.ticklabel_format(useLocale=True)

plt.show()

fig2.savefig("Mein_Test2.pdf")

The first figure looks as desired, with nice English points as decimal separators and nice spacing in the axis tick labels, and I can use the LaTeX "\le" symbol in the x axix label:

However, the second figure shows an ugly spacing in the numbers of axis tick labels, with too much space behind the decimal separator:

如果我这样做[[not使用“ matplotlib.rcParams ['text.usetex'] = True”，那么我不能在标签中包含LaTeX元素，即，没有” \ le“符号，但是要有空格即使对于德国逗号也是正确的。因此，德语语言环境与“ text.usetex”之间似乎存在一些冲突。任何想法都正确吗？谢谢！

Answer 1

[我最终找到了一种方法，也可以使用lambda函数通过查看this问题的答案来获得所需的结果。这是代码：

# -*- coding: utf-8 -*-
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

import locale

# Set to German locale to get comma decimal separater
locale.setlocale(locale.LC_NUMERIC, "deu_deu")

# Use LaTeX elements
mpl.rcParams['text.usetex'] = True

t = np.linspace(0.0, 1.0, 100)
s = t*np.cos(4 * np.pi * t) + 2

fig2, ax2 = plt.subplots(figsize=(6, 4))

ax2.ticklabel_format(useLocale=True)

ax2.plot(t, s)

ax2.set_xlabel(r'Time $t$ with $t \le 1$')
ax2.set_ylabel('Velocity $v(t)$')

plt.ticklabel_format(useLocale=True)


ax2.get_yaxis().set_major_formatter(mpl.ticker.FuncFormatter(lambda x, loc: locale.format_string('%1.3f', x, 1)))
ax2.get_xaxis().set_major_formatter(mpl.ticker.FuncFormatter(lambda x, loc: locale.format_string('%0.2f', x, 2)))

plt.show()

fig2.savefig("Mein_Test2.png")

现在我得到了desired result: