1.多边形绘图
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sun Oct 27 08:13:22 2019
@author: snow
"""
import matplotlib.pyplot as plt # 绘图的库
import numpy as np #python科学计算的库
x = np.linspace(0,2*np.pi,num=500) #x轴取值
y = np.sin(x) #y轴取值
#fill（）填充函数曲线与坐标轴之间的区域: alpha表示透明度
plt.fill(x,y, color="cornflowerblue",alpha=0.2)
# plot 绘制多边形的边框 color表示使用的颜色
plt.plot(x,y, color="black",alpha=0.8)
# 绘制中间红色横线
plt.plot([x[0],x[-1]],[y[0],y[-1]], color="red",alpha=1)
plt.ylim(0,2*np.pi) # 表示设置x左右边界
#plt.xlim(left=5)
left, right = plt.xlim()# 表示获取x轴左右边界
print(left)
print(right)
plt.ylim(-1.1,1.1)
# np.arange(0,16.1,1) ：产生从0到16.1的步长是1的序列
#plt.xticks(np.arange(0,16.1,1)) # 绘制x轴显示的数值
#plt.yticks(np.arange(0,16.1,1))
plt.savefig("a.png")
plt.show()#显示图片
图片如下:
a.png
2. fill_between的使用
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0,2,500)
y1 = np.sin(2*np.pi*x)
y2 = 1.2*np.sin(3*np.pi*x)
fig,ax = plt.subplots(3,1,sharex="all")
ax[0].fill_between(x,0,y2,alpha=0.5)
ax[0].set_ylim(-1.3,1.3)
ax[1].fill_between(x,y2,1.1,alpha=0.5)
ax[1].set_ylim(-1.3,1.3)
"""
x：第一个参数表示覆盖的区域，我直接复制为x，表示整个x都覆盖
y1：表示覆盖的下限
y2：表示覆盖的上限是y这个曲线
color ：覆盖区域的颜色
alpha：覆盖区域的透明度[0,1],其值越大，表示越不透明
"""
ax[2].fill_between(x,y1,y2,alpha=0.7,color='red')
ax[2].plot(x,y1)
ax[2].plot(x,y2,color="black")
ax[2].set_xlim(0,2)
ax[2].set_ylim(-1.3,1.3)
plt.savefig("b.png")
plt.show()
b.png
3. where 的使用
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0,2,500)
y1 = np.sin(2*np.pi*x)
y2 = 1.1*np.sin(3*np.pi*x)
fig = plt.figure()
ax = fig.add_subplot(111)
# plot y1 and plot y2
ax.plot(x,y1,color="k",lw=1,ls="-")
ax.plot(x,y2,color="k",lw=1,ls="-")
# "where y1 <= y2"
# 结果如图所示
ax.fill_between(x,y1,y2,where=y2>=y1,interpolate=True,
facecolor="cornflowerblue",alpha=0.7)
# where y1>= y2
ax.fill_between(x,y1,y2,where=y2<=y1,interpolate=True,
facecolor="darkred",alpha=0.7)
ax.set_xlim(0,2)
ax.set_ylim(-1.2,1.2)
# 添加虚线方格
ax.grid(ls=":",lw=1,color="gray",alpha=0.5)
plt.savefig("04.png")
plt.show()
04.png
4. x 和 y 互换
import matplotlib.pyplot as plt
import numpy as np
y = np.linspace(0,2,500)
x1 = np.sin(2*np.pi*y)
x2 = 1.1*np.sin(3*np.pi*y)
fig = plt.figure()
ax = fig.add_subplot(111)
# plot x1 and plot x2
ax.plot(x1,y,color="k",lw=1,ls="-")
ax.plot(x2,y,color="k",lw=1,ls="-")
# "where x1 <= x2"
ax.fill_betweenx(y,x1,x2,where=x2>=x1,facecolor="cornflowerblue",alpha=0.7)
# where x1>= x2
ax.fill_betweenx(y,x1,x2,where=x2<=x1,facecolor="darkred",alpha=0.7)
ax.set_xlim(-1.2,1.2)
ax.set_ylim(0,2)
ax.grid(ls=":",lw=1,color="gray",alpha=0.5)
plt.savefig("05.png")
plt.show()
05.png
**5. mask **
import matplotlib.pyplot as plt
import numpy as np
fig,ax = plt.subplots(1,2)
# subplot(121) data
x = np.linspace(0,2,500)
y1 = np.sin(2*np.pi*x)
y2 = 1.2*np.sin(3*np.pi*x)
y2 = np.ma.masked_greater(y2,1.0)
# plot y1 and plot y2
ax[0].plot(x,y1,color="k",lw=1,ls="-")
ax[0].plot(x,y2,color="k",lw=1,ls="-")
# "where y1 <= y2"
ax[0].fill_between(x,y1,y2,where=y2>=y1,facecolor="cornflowerblue",alpha=0.7)
# where y1>= y2
ax[0].fill_between(x,y1,y2,where=y2<=y1,facecolor="darkred",alpha=0.7)
ax[0].set_xlim(0,2)
ax[0].set_ylim(-1.2,1.2)
ax[0].grid(ls=":",lw=1,color="gray",alpha=0.5)
# subplot(122) data
y = np.linspace(0,2,500)
x1 = np.sin(2*np.pi*y)
x2 = 1.2*np.sin(3*np.pi*y)
x2 = np.ma.masked_greater(x2,1.0)
# plot x1 and plot x2
ax[1].plot(x1,y,color="k",lw=1,ls="-")
ax[1].plot(x2,y,color="k",lw=1,ls="-")
# "where x1 <= x2"
ax[1].fill_betweenx(y,x1,x2,where=x2>=x1,facecolor="cornflowerblue",alpha=0.7)
# where x1>= x2
ax[1].fill_betweenx(y,x1,x2,where=x2<=x1,facecolor="darkred",alpha=0.7)
ax[1].set_xlim(-1.2,1.2)
ax[1].set_ylim(0,2)
ax[1].grid(ls=":",lw=1,color="gray",alpha=0.5)
plt.savefig("06.png")
plt.show()
06.png
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