python 添加图例_Python | 在图上添加图例

ゞ浴缸里的玫瑰 2023-03-05 10:58 16阅读 0赞

python 添加图例

**Adding legend** is the best way to label data series plotted on a graph. Matplotlib has an inbuilt defined function for our adding legend operation. The legend can be added to any type of plot such as line plot, [dot plot][], [scatter plot][], bar plot, etc. Following are some examples showing the implementation of matplotlib.pyplot.legend().

**添加图例**是标记图上绘制的数据系列的最佳方法。 Matplotlib有一个内置的定义函数，用于添加图例操作。 可以将图例添加到任何类型的绘图中，例如线图， [点图][dot plot] ， [散点图][scatter plot] ，条形图等。以下是一些示例，显示了matplotlib.pyplot.legend()的实现。

![Python | Adding legend to a Plot (1)][Python _ Adding legend to a Plot _1]

![Python | Adding legend to a Plot (2)][Python _ Adding legend to a Plot _2]

![Python | Adding legend to a Plot (3)][Python _ Adding legend to a Plot _3]

**References:** [https://matplotlib.org/][https_matplotlib.org], [https://in.mathworks.com/][https_in.mathworks.com]

**参考：** [https][https_matplotlib.org] **:** [//matplotlib.org/，https][https_matplotlib.org] : [//in.mathworks.com/][https_in.mathworks.com]

## 用于将图例添加到图的Python代码 **(**Python code for adding legend to a plot**)** ##

# Data Visualization using Python
    # Adding a Legend
    
    import numpy as np
    import matplotlib.pyplot as plt
    
    x = np.linspace(0, 2, 100)
    
    # Example 1
    plt.figure()
    plt.plot(x, x+2, label='linear')  
    plt.plot(x, x**2, label='quadratic')  
    plt.plot(x, x**3, label='cubic')
    plt.xlabel('x label')
    plt.ylabel('y label')
    plt.title("Legend Example 1")
    plt.legend()
    
    # Example 2
    plt.figure()
    x = np.linspace(0.0, 5.0)
    y = x*x
    plt.subplot(2, 1, 2)
    plt.plot(x, y, 'g.-',label='quadratic')
    plt.plot(x,x, 'r.-', label='linear')
    plt.title('Legend Example 2')
    plt.xlabel('numbers')
    plt.ylabel('Square')
    plt.legend()
    plt.show()
    
    # Example 3
    # Random Bar Graph Example
    plt.figure()
    plt.barh(np.arange(26), np.random.randint(0,50,26), alpha = 0.5, color='r', label='Legend Bar Graph')
    plt.title('Horizontal Bar Graph : Random')
    plt.legend()

**Output:**

**输出：**

Output is as figure

> 翻译自: [https://www.includehelp.com/python/adding-legend-to-a-plot.aspx][https_www.includehelp.com_python_adding-legend-to-a-plot.aspx]

python 添加图例

[dot plot]: https://www.includehelp.com/python/dot-plot.aspx
[scatter plot]: https://www.includehelp.com/python/scatter-plot.aspx
[Python _ Adding legend to a Plot _1]: /images/20230208/6132835d580e48dda05b073c3bf98174.png
[Python _ Adding legend to a Plot _2]: /images/20230208/31247569b1ac4a38b57e6ce86cab6833.png
[Python _ Adding legend to a Plot _3]: /images/20230208/44a670f76ffc4ccc84359282f121b15e.png
[https_matplotlib.org]: https://matplotlib.org/
[https_in.mathworks.com]: https://in.mathworks.com/
[https_www.includehelp.com_python_adding-legend-to-a-plot.aspx]: https://www.includehelp.com/python/adding-legend-to-a-plot.aspx