matplotlib.pyplot基础（二），柱面图，散点图，坐标系填充

绝地灬酷狼 2022-06-06 01:10 183阅读 0赞

（1）柱面图plt.bar

# 柱面图plt.bar
    import numpy as np
    import matplotlib.pyplot as plt
    plt.figure()
    n = 8
    X = np.arange(n)+1
    #X是1,2,3,4,5,6,7,8,柱的个数
    # numpy.random.uniform(low=0.0, high=1.0, size=None), normal
    #uniform均匀分布的随机数，normal是正态分布的随机数，0.5-1均匀分布的数，一共有n个
    Y1 = np.random.uniform(0.5,1.0,n)
    Y2 = np.random.uniform(0.5,1.0,n)
    #width:柱的宽度,facecolor:柱面的颜色，edgecolor:柱的边界颜色
    plt.bar(X,Y1,width = 0.35,facecolor = 'blue',edgecolor = 'red')
    # 可以再添加一些柱条，添加-号可以将柱面反过来
    plt.bar(X+0.35,-Y2,width = 0.35,facecolor = 'yellow',edgecolor = 'black')
    # 水平柱状图plt.barh，属性中宽度width变成了高度height
    #给图加text
    for x,y in zip(X,Y1):
        plt.text(x+0.3, y+0.05, '%.2f' % y, ha='center', va= 'bottom')
    
    for x,y in zip(X,Y2):
        plt.text(x+0.6, -y-0.05, '%.2f' % y, ha='center', va= 'bottom')
    plt.ylim(-1.25,+1.25)
    plt.show()

![这里写图片描述][SouthEast]

（2）散点图plt.scatter

#散点图plt.scatter
    import numpy as np
    import matplotlib.pyplot as plt
    plt.figure()
    n=1000
    #rand 均匀分布和 randn高斯分布
    x=np.random.randn(1,n)
    y=np.random.randn(1,n)
    #c:散点的颜色，s：散点的大小，alpha:是透明程度
    plt.scatter(x,y,c='red',s=25,alpha=0.4,marker='o')
    plt.show()

![这里写图片描述][SouthEast 1]

（3）坐标系填充颜色plt.pcolormesh

# plt.pcolormesh给坐标填充颜色，分开填色
    import numpy as np
    import matplotlib.pyplot as plt
    h = 0.5
    x_min = 0
    x_mid = 5
    x_max = 10
    y_min = 0
    y_mid = 5
    y_max = 10
    xx1, yy1 = np.meshgrid(np.arange(x_min, x_mid, h),
                             np.arange(y_min, y_mid, h))
    xx2, yy2 = np.meshgrid(np.arange(x_mid, x_max, h),
                             np.arange(y_mid, y_max, h))
    z1 = np.ones(xx1.shape)
    z2 = np.zeros(xx2.shape)
    # 分开填色
    plt.pcolormesh(xx1,yy1,z1,cmap=plt.cm.Paired)
    plt.pcolormesh(xx2,yy2,z2,cmap=plt.cm.Paired)
    plt.show()

![这里写图片描述][SouthEast 2]

同时填色

# 同时填色
    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib.colors import ListedColormap
    cmap_light = ListedColormap(['#FFAAAA', '#AAFFAA'])
    h = 0.5
    x_min = 0
    x_mid = 5
    x_max = 10
    y_min = 0
    y_mid = 5
    y_max = 10
    xx3, yy3 = np.meshgrid(np.arange(x_min, x_max, h),
                             np.arange(y_min, y_max, h))
    z3 =np.zeros(xx3.shape)
    m,n = xx3.shape
    z3[:m/2] = 1
    plt.pcolormesh(xx3,yy3,z3,cmap=cmap_light)
    plt.show()

![这里写图片描述][SouthEast 3]

[SouthEast]: /images/20220606/cfd450b9484a4f9b99a9bcf9cd44bf27.png
[SouthEast 1]: /images/20220606/9713e56d0adf47a89ca4c2b61583f765.png
[SouthEast 2]: /images/20220606/5bc0e6d4f9da4102a6c7bc1b8e679a4c.png
[SouthEast 3]: /images/20220606/7e3344f9d17841babd4bd63209c9a01c.png