Matplotlib 简明教程

Matplotlib - Multiplots

在本章中，我们将学习如何在同一画布上创建多个子图。

In this chapter, we will learn how to create multiple subplots on same canvas.

subplot() 函数返回给定网格位置处的Axes对象。此函数的调用签名为：

The subplot() function returns the axes object at a given grid position. The Call signature of this function is −

plt.subplot(subplot(nrows, ncols, index)

在当前图形中，该函数创建一个Axes对象，并将其返回到nrows by ncolsaxes网格的位置索引处。索引从1到nrows * ncols，以行优先顺序递增。如果nrows、ncols和index均小于10。索引也可以表示为单个、连接的、三位数字。

In the current figure, the function creates and returns an Axes object, at position index of a grid of nrows by ncolsaxes. Indexes go from 1 to nrows * ncols, incrementing in row-major order.Ifnrows, ncols and index are all less than 10. The indexes can also be given as single, concatenated, threedigitnumber.

例如，subplot(2, 3, 3)和subplot(233)都在当前图形的右上角创建一个Axes，占据图形高度的一半和图形宽度的三分之一。

For example, subplot(2, 3, 3) and subplot(233) both create an Axes at the top right corner of the current figure, occupying half of the figure height and a third of the figure width.

创建子图将删除其与超出共享边界的任何预先存在的子图重叠。

Creating a subplot will delete any pre-existing subplot that overlaps with it beyond sharing a boundary.

import matplotlib.pyplot as plt
# plot a line, implicitly creating a subplot(111)
plt.plot([1,2,3])
# now create a subplot which represents the top plot of a grid with 2 rows and 1 column.
#Since this subplot will overlap the first, the plot (and its axes) previously
created, will be removed
plt.subplot(211)
plt.plot(range(12))
plt.subplot(212, facecolor='y') # creates 2nd subplot with yellow background
plt.plot(range(12))

上述代码行生成以下输出 -

The above line of code generates the following output −

mutliplots

图形类的add_subplot()函数不会覆盖现有绘图：

The add_subplot() function of the figure class will not overwrite the existing plot −

import matplotlib.pyplot as plt
fig = plt.figure()
ax1 = fig.add_subplot(111)
ax1.plot([1,2,3])
ax2 = fig.add_subplot(221, facecolor='y')
ax2.plot([1,2,3])

当执行上述代码行时，它生成以下输出：

When the above line of code is executed, it generates the following output −

add subplot function

您可以通过在同一图形画布中添加另一个Axes对象，在同一图形中添加一个插入绘图。

You can add an insert plot in the same figure by adding another axes object in the same figure canvas.

import matplotlib.pyplot as plt
import numpy as np
import math
x = np.arange(0, math.pi*2, 0.05)
fig=plt.figure()
axes1 = fig.add_axes([0.1, 0.1, 0.8, 0.8]) # main axes
axes2 = fig.add_axes([0.55, 0.55, 0.3, 0.3]) # inset axes
y = np.sin(x)
axes1.plot(x, y, 'b')
axes2.plot(x,np.cos(x),'r')
axes1.set_title('sine')
axes2.set_title("cosine")
plt.show()

当执行上述代码行时，生成以下输出：

Upon execution of the above line of code, the following output is generated −

insert plot