Python_matplotlib库的使用（画函数图像、扇形图）

川长思鸟来 2022-12-19 00:52 407阅读 0赞

# 画函数图像 #

先来看几个栗子：

绘制y=2sinx+cosx的曲线，横坐标为\[-3*pi,3*pi\],曲线为红色

import matplotlib.pyplot as plt
    import numpy as np
    
    x=np.linspace(-3*np.pi,3*np.pi,256,endpoint=80) #图像横坐标范围
    y=np.sin(x)*2+np.cos(x)
    plt.xlim(-3*np.pi,3*np.pi) #坐标轴横坐标取值范围
    
    plt.plot(x,y,color='red',linewidth=5,linestyle='-') #根据x y 数组绘制直线曲线
    plt.show()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ2NjcyNzQ2_size_16_color_FFFFFF_t_70_pic_center]  
一个图里两个图像的：

import numpy as np
    import matplotlib.pyplot as plt
    import math
    
    x=np.linspace(-np.pi,np.pi,256,endpoint=80)
    y1=np.cos(2*np.pi*x)
    y2=1/(math.e**x)*np.cos(2*np.pi*x)
    
    plt.plot(x,y1,label="y1=cos(2*pi*x)")
    plt.plot(x,y2,label='(1/e**x)*cos(2*pi*x)')
    plt.legend(loc=1)
    plt.xlabel('x')
    plt.ylabel('y')
    
    plt.show()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ2NjcyNzQ2_size_16_color_FFFFFF_t_70_pic_center 1]

# 扇形图 #

#-*- coding: utf-8 -*-
    from matplotlib import pyplot as plt
    plt.rcParams['font.sans-serif']=['SimHei'] #解决中文乱码
    
    plt.figure(figsize=(6,9)) #调节图形大小
    labels = [u'Dogs',u'Hogs',u'Frogs',u'Logs'] #定义标签
    sizes = [45, 30, 15, 10] #每块值
    colors = ['green', 'yellow', 'blue', 'red'] #每块颜色定义
    explode = (0,0,0,0) #将某一块分割出来，值越大分割出的间隙越大
    patches,text1,text2 = plt.pie(sizes,
                          explode=explode,
                          labels=labels,
                          colors=colors,
                          autopct = '%3.2f%%', #数值保留固定小数位
                          shadow = False, #无阴影设置
                          startangle =90, #逆时针起始角度设置
                          pctdistance = 0.6) #数值距圆心半径倍数距离
    #patches饼图的返回值，texts1饼图外label的文本，texts2饼图内部的文本
    # x，y轴刻度设置一致，保证饼图为圆形
    plt.axis('equal')
    plt.legend() # 右上角显示
    plt.show()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ2NjcyNzQ2_size_16_color_FFFFFF_t_70_pic_center 2]  
有阴影

> shadow = True, \#有阴影设置

plt.figure(figsize=(6,9)) #调节图形大小
    plt.figure(figsize=(6,9)) #调节图形大小
    labels = [u'Dogs',u'Hogs',u'Frogs',u'Logs'] #定义标签
    sizes = [45, 30, 15, 10] #每块值
    colors = ['green', 'yellow', 'blue', 'red'] #每块颜色定义
    patches,text1,text2 = plt.pie(sizes,
                          explode=explode,
                          labels=labels,
                          colors=colors,
                          autopct = '%3.2f%%', #数值保留固定小数位
                          shadow = True, #有阴影设置
                          startangle =90, #逆时针起始角度设置
                          pctdistance = 0.6) #数值距圆心半径倍数的距离
    #patches饼图的返回值，texts1饼图外label的文本，texts2饼图内部的文本
    # x，y轴刻度设置一致，保证饼图为圆形
    plt.axis('equal')
    plt.show()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ2NjcyNzQ2_size_16_color_FFFFFF_t_70_pic_center 3]  
分隔开

> explode=(0, 0.07, 0, 0)

plt.figure(figsize=(6,9)) #调节图形大小
    labels = [u'Frogs', u'Hogs', u'Dogs', u'Logs'] #定义标签
    sizes = [15, 30, 45, 10] #每块值
    colors = ['blue', 'orange', 'green', 'red'] #每块颜色定义
    explode=(0, 0.07, 0, 0) 
    patches,text1,text2 = plt.pie(sizes,
                          explode=explode,
                          labels=labels,
                          colors=colors,
                          labeldistance = 1.2,#图例距圆心半径倍距离  
                          autopct = '%3.2f%%', #数值保留固定小数位
                          shadow = False, #无阴影
                          startangle =90, #逆时针起始角度设置
                          pctdistance = 0.6) #数值距圆心半径倍数距离
    #patches饼图的返回值，texts1饼图外label的文本，texts2饼图内部文本
    # x，y轴刻度设置一致，保证饼图为圆形
    plt.axis('equal')
    plt.show()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ2NjcyNzQ2_size_16_color_FFFFFF_t_70_pic_center 4]

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