Python 如何以分数标记x轴？

我想使用分数标记轴，以准确显示数据点的位置。例如，在下面的代码中，我想标记x轴“1/13,2/13,3/13…”

如何做到这一点

import numpy as np
import math 
import matplotlib.pyplot as plt

step=1./13.
x=np.arange(0,14)*step
y=np.sin(2*np.pi*x)
plt.plot(x,y,'r*')
plt.show()

两件事

您需要设置记号标签

请参阅此处以获取详细答案：

您需要将标签格式化为分数。 在这里，您可以为每个标签生成一个字符串： 类似这样的东西（未经测试）

您可以使用模块完成此操作。我们需要使用

ax.xaxis.set_major_locator

及

我们将使用a将记号放置在给定的分数上（即

步骤

的每一个倍数），然后使用a将记号标签呈现为分数

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker

step=1./13.
x=np.arange(0,14)*step
y=np.sin(2*np.pi*x)

fig,ax = plt.subplots()

ax.plot(x,y,'r*')

def fractions(x,pos):
    if np.isclose((x/step)%(1./step),0.):
        # x is an integer, so just return that
        return '{:.0f}'.format(x)
    else:
        # this returns a latex formatted fraction
        return '$\\frac{{{:2.0f}}}{{{:2.0f}}}$'.format(x/step,1./step)
        # if you don't want to use latex, you could use this commented
        # line, which formats the fraction as "1/13"
        ### return '{:2.0f}/{:2.0f}'.format(x/step,1./step)

ax.xaxis.set_major_locator(ticker.MultipleLocator(step))
ax.xaxis.set_major_formatter(ticker.FuncFormatter(fractions))

plt.show()

ax.xaxis.set_major_formatter

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker

step=1./13.
x=np.arange(0,14)*step
y=np.sin(2*np.pi*x)

fig,ax = plt.subplots()

ax.plot(x,y,'r*')

def fractions(x,pos):
    if np.isclose((x/step)%(1./step),0.):
        # x is an integer, so just return that
        return '{:.0f}'.format(x)
    else:
        # this returns a latex formatted fraction
        return '$\\frac{{{:2.0f}}}{{{:2.0f}}}$'.format(x/step,1./step)
        # if you don't want to use latex, you could use this commented
        # line, which formats the fraction as "1/13"
        ### return '{:2.0f}/{:2.0f}'.format(x/step,1./step)

ax.xaxis.set_major_locator(ticker.MultipleLocator(step))
ax.xaxis.set_major_formatter(ticker.FuncFormatter(fractions))

plt.show()