Matplotlib 简明教程
Matplotlib - Radian Ticks
弧度是用于在数学和物理学中表示角度的角量单位。刻度，在数据可视化领域，是指指示轴度量的短线或标记。
A radian is a unit of angular measure used to express angles in mathematics and physics. Ticks, in the field of data visualization, refer to the small lines or marks indicating the scale of the axes.
Radian Ticks in Matplotlib
在 Matplotlib 的上下文中，弧度刻度通常表示轴上的刻度或标记，表示弧度中的值。当处理循环或角数据时，通常在轴上使用弧度刻度来表示特定角度。设置弧度刻度包括在轴上与特定弧度值对应的特定间隔处放置刻度标记。
In the context of Matplotlib, radian ticks typically denote the ticks or markers on an axis that represent values in radians. When dealing with circular or angular data, it is common to use radian ticks on the axis to indicate specific angles. Setting radian ticks involves placing tick marks at specific intervals corresponding to certain radian values on the axis.
下面是一幅参考图像，说明了绘图中的弧度刻度 −
Here is a reference image illustrating Radian ticks on a plot −
在该图像中，你可以观察到弧度刻度表示了正弦波沿 x 轴的角度。
In the image, you can observe that radian ticks represent the angles of the sine wave along the x-axis.
Radian Ticks for the x axis
为 x 轴设置弧度刻度涉及使用两个关键方法，即 axes.set_xticks() 和 axes.set_xticklabels()。这些方法分别允许你指定 x 轴上刻度的定位和标签。
Setting Radian Ticks for the x-axis involves using two key methods which are axes.set_xticks() and axes.set_xticklabels(). These methods are allowing you to specify the positions and labels of ticks on the x-axis, respectively.
除了这些方法外，matplotlib.ticker 模块中的 FormatStrFormatter 和 MultipleLocator 类可用于增强刻度定位和标签的自定义。
In addition to these methods, the FormatStrFormatter and MultipleLocator classes from the matplotlib.ticker module can be used to enhance the customization of tick positions and labels.
Example 1
下面的示例演示了如何创建带自定义弧度刻度的绘图。
The following example demonstrates how to create a plot with custom radian ticks.
import matplotlib.pyplot as plt
import numpy as np
# Create plot
fig, ax = plt.subplots(figsize=(7, 4))
# Sample data
theta = np.linspace(0, 2 * np.pi, 100)
y = np.sin(theta)
# Plotting the data
plt.plot(theta, y)
plt.title('Sine Wave')
plt.xlabel('Angle (radians)')
plt.ylabel('Y-axis')
# Custom radian ticks and tick labels
custom_ticks = [0, np.pi/2, np.pi, (3*np.pi)/2, 2*np.pi]
custom_tick_labels = ['$0$', '$\pi/2$', '$\pi$', '$3\pi/2$', '$2\pi$']
ax.set_xticks(custom_ticks)
ax.set_xticklabels(custom_tick_labels)
plt.grid(axis='x')
# Display the plot
plt.show()执行上述代码，我们将得到以下输出 −
On executing the above code we will get the following output −
Example 2
此示例使用 FormatStrFormatter 和 MultipleLocator 模块中的 matplotlib.ticker 类来控制刻度的格式和定位。
This example uses the FormatStrFormatter and MultipleLocator classes from the matplotlib.ticker module to control the format and positions of ticks.
import matplotlib.pyplot as plt
import matplotlib.ticker as tck
import numpy as np
# Create Plot
f,ax=plt.subplots(figsize=(7,4))
# Sample Data
x=np.linspace(0, 2 * np.pi, 100)
y=np.sin(x)
# Plot the sine wave
ax.plot(x/np.pi,y)
# Customizing X-axis Ticks
ax.xaxis.set_major_formatter(tck.FormatStrFormatter('%g $\pi$'))
ax.xaxis.set_major_locator(tck.MultipleLocator(base=1.0))
# Set the titles
plt.title('Sine Wave')
plt.xlabel('Angle (radians)')
plt.ylabel('Y-axis')
plt.grid()
plt.show()执行上述代码，我们将得到以下输出 −
On executing the above code we will get the following output −
Radian Ticks for the y axis
类似于 x 轴，为 y 轴设置弧度刻度可以通过使用 ax.set_yticks() 和 ax.set_yticklabels() 方法来完成。这些方法允许你定义 y 轴上刻度的定位和标签。此外，matplotlib.ticker 模块中的 FormatStrFormatter 和 MultipleLocator 类也可以使用。
Similar to the x-axis, setting radian ticks for the y-axis can be done by using the ax.set_yticks() and ax.set_yticklabels() methods. These methods allow you to define the positions and labels of ticks on the y-axis. Additionally, the FormatStrFormatter and MultipleLocator classes from the matplotlib.ticker module can also used.
Example
此示例演示了如何为 y 轴设置自定义弧度刻度，使用了 FormatStrFormatter 和 MultipleLocator 模块中的 matplotlib.ticker 类。
This example demonstrates how to set customized radian ticks for the y-axis. using the FormatStrFormatter and MultipleLocator classes from the matplotlib.ticker module.
import matplotlib.pyplot as plt
import matplotlib.ticker as tck
import numpy as np
# Create Plot
f,ax=plt.subplots(figsize=(7,4))
# Sample Data
x=np.arange(-10.0,10.0,0.1)
y=np.arctan(x)
# Plot the data
ax.plot(x/np.pi,y)
# Customizing y-axis Ticks
ax.yaxis.set_major_formatter(tck.FormatStrFormatter('%g $\pi$'))
ax.yaxis.set_major_locator(tck.MultipleLocator(base=0.5))
plt.grid()
plt.show()执行上述代码，我们将得到以下输出 −
On executing the above code we will get the following output −
Custom Package for Radian Ticks
名为 “basic_units.py” 的自定义程序包可以用弧度表示刻度标记。此程序包不是标准或广泛认可的程序包的一部分，需要单独下载（可在 Matplotlib 的示例文件夹中找到）。
A custom package named "basic_units.py" can denote the tick marks using the radians. This package is not part of the standard or widely recognized packages and needs to be downloaded separately(available in the examples folder of Matplotlib).
Example
本示例展示了如何使用 basic_units 模拟示例包使用弧度创建绘图。
This example demonstrates how to create a plot with radians using the basic_units mockup example package.
import matplotlib.pyplot as plt
from basic_units import radians
import numpy as np
# Create Plot
f,ax=plt.subplots(figsize=(7,4))
x = np.arange(-10.0,10.0,0.1)
y = list(map(lambda y: y*radians,np.arctan(x)))
x = list(map(lambda x: x*radians,x))
ax.plot(x,y,'b.')
plt.xlabel('radians')
plt.ylabel('radians')
plt.show()执行上述代码，我们将得到以下输出 −
On executing the above code we will get the following output −
