源码：
1 import numpy as np
2 import matplotlib.pyplot as plt
3 import math
4
5
6 def normal_distribution(x, mean, sigma):
7 return np.exp(-1 * ((x - mean) ** 2) / (2 * (sigma ** 2))) / (math.sqrt(2 * np.pi) * sigma)
8
9
10 mean1, sigma1 = 0, 1
11 x1 = np.linspace(mean1 - 6 * sigma1, mean1 + 6 * sigma1, 100)
12
13 mean2, sigma2 = 0, 2
14 x2 = np.linspace(mean2 - 6 * sigma2, mean2 + 6 * sigma2, 100)
15
16 mean3, sigma3 = 5, 1
17 x3 = np.linspace(mean3 - 6 * sigma3, mean3 + 6 * sigma3, 100)
18
19 y1 = normal_distribution(x1, mean1, sigma1)
20 y2 = normal_distribution(x2, mean2, sigma2)
21 y3 = normal_distribution(x3, mean3, sigma3)
22
23 plt.plot(x1, y1, 'r', label='m=0,sig=1')
24 plt.plot(x2, y2, 'g', label='m=0,sig=2')
25 plt.plot(x3, y3, 'b', label='m=1,sig=1')
26 plt.legend()
27 plt.grid()
28 plt.show()
效果图：
源码：
import turtle
# 定义大圆半径200,则小圆半径big_radius * 0.5, 假如内部最小圆半径为big_radius*0.15
big_radius = 200
def main():
turtle.reset()
turtle.shape("turtle")
yin("black", "white", 1)
yin("white", "black", -1)
turtle.ht()
def yin(big_fillcolor, inner_fillcolor, direction):
"""
画一半阴阳八卦
:param big_fillcolor: 外部大圆填充色
:param inner_fillcolor: 内部小圆填充色
:param direction: 1表示开始默认开始方向向右,-1表示开始默认开始方向向左
:return:
"""
turtle.pensize(3)
# 设置pencolor和fillcolor
turtle.color("black", big_fillcolor)
# 开始填充
turtle.begin_fill()
# 画内半圆
turtle.circle(big_radius / 2.0, 180)
# 画外半圆
turtle.circle(big_radius, 180)
# 海龟箭头左转180度
turtle.lt(180)
# 反方向画内半圆,反方向画圆,半径前要加 -
turtle.circle(-big_radius / 2.0, 180)
# 结束填充
turtle.end_fill()
# 画笔抬起
turtle.pu()
# 从画笔当前位置开始画圆,因此需要减去内圆半径,y方向移动,x方向不变
turtle.sety(direction * big_radius * (0.5 - 0.15))
# 画笔放下
turtle.pd()
# 设置pencolor和fillcolor
turtle.color(big_fillcolor, inner_fillcolor)
# 开始填充内圆
turtle.begin_fill()
# 画内圆
turtle.circle(big_radius * 0.15)
# 结束填充内圆
turtle.end_fill()
# 画笔抬起
turtle.pu()
# 海龟箭头回到(0, 0)坐标
turtle.goto(0, 0)
# 画笔放下
turtle.pd()
# 海龟箭头左转180度
turtle.lt(180)
return "Done!"
if __name__ == '__main__':
main()
turtle.mainloop()
效果图：
