# 设置X轴限制后填充图之间的区域

``````df = pd.DataFrame({'DEPTH': [100, 150, 200, 250, 300, 350, 400, 450, 500, 550],
'PERMEABILITY': [1000, 800, 900, 600, 200, 250, 400, 300, 100, 200],
'POROSITY': [0.30, 0.25, 0.15, 0.19, 0.15, 0.10, 0.15, 0.19, 0.10, 0.15]})

f, ax1 = plt.subplots()

ax1.set_xlabel('PERMEABILITY')
ax1.set_ylabel('DEPTH')
ax1.set_ylim(df['DEPTH'].max(), df['DEPTH'].min())

ax1.plot(df['PERMEABILITY'], df['DEPTH'], color='red')
ax1.tick_params(axis='x', labelcolor='red')

ax2 = ax1.twiny()

ax2.set_xlabel('POROSITY')
ax2.plot(df['POROSITY'], df['DEPTH'], color='blue')
ax2.tick_params(axis='x', labelcolor='blue')

# convert POROSITY axis to PERMEABILITY
# value-min / range -> normalized POROSITY (normp)
# normp*newrange + newmin -> stretched POROSITY to PERMEABILITY
z=df['POROSITY']
x=df['PERMEABILITY']
nz=((z-np.min(z))/(np.max(z)-np.min(z)))*(np.max(x)-np.min(x))+np.min(x)

# fill between in green where PERMEABILITY is larger
ax1.fill_betweenx(df['DEPTH'],x,nz,where=x>=nz,interpolate=True,color='g')
# fill between in yellow where POROSITY is larger
ax1.fill_betweenx(df['DEPTH'],x,nz,where=x<=nz,interpolate=True,color='y')
plt.show()
``````

``````ax1.set_xlim(0, 1500)
ax2.set_xlim(-0.10, 0.45)
``````