如何更改 matplotlib 中的颜色条标签？

在本文中，我们将了解如何使用Python在 matplotlib 中更改颜色条标签。

colorbar()函数用于绘制颜色条，它属于 matplotlib 的 pyplot 模块，在绘图中添加了一个颜色条，指示色标。

Syntax: matplotlib.pyplot.colorbar(mappable=None, cax=None, ax=None, **kwarg)

Parameters:

• ax: This parameter is an optional parameter and it contains Axes or list of Axes.
• **kwarg(keyword arguments): This parameter is an optional parameter and are of two kinds:
• colorbar properties:
• extend:{‘neither’, ‘both’, ‘min’, ‘max’} makes pointed end(s) for out-of-range values.
• label:The label on the colorbar’s long axis.
• ticks:None or list of ticks or Locator.

Returns:colorbar which is an instance of the class ‘matplotlib.colorbar.Colorbar’.     

创建一个简单的颜色条进行演示

要创建颜色条，我们将使用 color() 方法，为此，我们将创建数据集，然后使用散点图进行演示。

Python3

# Python Program illustrating
# pyplot.colorbar() method
import numpy as np
import matplotlib.pyplot as plt
 
# Dataset
# List of total number of items purchased
# from each products
purchaseCount = [100, 200, 150, 23, 30, 50,
                156, 32, 67, 89]
 
# List of total likes of 10 products
likes = [50, 70, 100, 10, 10, 34, 56, 18, 35, 45]
 
# List of Like/Dislike ratio of 10 products
ratio = [1, 0.53, 2, 0.76, 0.5, 2.125, 0.56,
        1.28, 1.09, 1.02]
 
# scatterplot
plt.scatter(x=purchaseCount, y=likes, c=ratio, cmap="summer")
 
plt.colorbar()
plt.show()

输出：

方法 1：更改颜色标签中的标签字体大小

要更改标签的字体大小，我们将使用ax.tick_params()方法来增加标签的字体。

Python3

# Python Program illustrating
# pyplot.colorbar() method
import numpy as np
import matplotlib.pyplot as plt
 
# Dataset
# List of total number of items purchased
# from each products
purchaseCount = [100, 200, 150, 23, 30, 50,
                156, 32, 67, 89]
 
# List of total likes of 10 products
likes = [50, 70, 100, 10, 10, 34, 56, 18, 35, 45]
 
# List of Like/Dislike ratio of 10 products
ratio = [1, 0.53, 2, 0.76, 0.5, 2.125, 0.56,
        1.28, 1.09, 1.02]
 
# scatterplot
plt.scatter(x=purchaseCount, y=likes, c=ratio,
            cmap="summer")
 
plt.colorbar().ax.tick_params(labelsize=10)
 
plt.show()

输出：

方法二：改变和旋转标签的位置

要旋转颜色条标签，我们将对水平和垂直使用 set_xticklabels() 和 set_yticklabels() 方法。

示例 1：水平更改位置

Python3

# Python Program illustrating
# pyplot.colorbar() method
import numpy as np
import matplotlib.pyplot as plt
 
# Dataset
# List of total number of items purchased
# from each products
purchaseCount = [100, 200, 150, 23, 30, 50,
                156, 32, 67, 89]
 
# List of total likes of 10 products
likes = [50, 70, 100, 10, 10, 34, 56, 18, 35, 45]
 
# List of Like/Dislike ratio of 10 products
ratio = [1, 0.53, 2, 0.76, 0.5, 2.125, 0.56,
        1.28, 1.09, 1.02]
 
# scatterplot
plt.scatter(x=purchaseCount, y=likes, c=ratio,
            cmap="summer")
 
plt.colorbar().ax.set_ylabel('Label',
                             rotation=120)
 
plt.show()

输出：

示例 2：垂直更改位置

Python3

# Python Program illustrating
# pyplot.colorbar() method
import numpy as np
import matplotlib.pyplot as plt
 
# Dataset
# List of total number of items purchased
# from each products
purchaseCount = [100, 200, 150, 23, 30, 50,
                156, 32, 67, 89]
 
# List of total likes of 10 products
likes = [50, 70, 100, 10, 10, 34, 56, 18, 35, 45]
 
# List of Like/Dislike ratio of 10 products
ratio = [1, 0.53, 2, 0.76, 0.5, 2.125, 0.56,
        1.28, 1.09, 1.02]
 
# scatterplot
plt.scatter(x=purchaseCount, y=likes, c=ratio, cmap="summer")
plt.colorbar(orientation="horizontal").ax.set_xticklabels(ratio, rotation=45)
 
plt.show()

输出：