matplotlib - use fill_between in python to shade a sub area of a density curve

Question

I would like to Fill_Between a sub section of a normal distribution, say the left 5%tile.

import numpy as np
import matplotlib.pyplot as plt
from scipy import stats as stats
plt.style.use('ggplot')
mean=1000
std=250
x=np.linspace(mean-3*std, mean+3*std,1000)
iq=stats.norm(mean,std)
plt.plot(x,iq.pdf(x),'b')

Great so far.

Then I set px to fill the area between x=0 to 500

px=np.arange(0,500,10)
plt_fill_between(px,iq.pdf(px),color='r')

The problem is that the above will only show the pdf from 0 to 500 in red. I want to show the full pdf from 0 to 2000 where the 0 to 500 is shaded? Any idea how to create this?

Answer 1

As commented, you need to use plt.fill_between instead of plt_fill_between. When doing so the output looks like this which seems to be exactly what you're looking for.

import numpy as np
import matplotlib.pyplot as plt
from scipy import stats as stats
plt.style.use('ggplot')
mean=1000
std=250
x=np.linspace(mean-3*std, mean+3*std,1000)
iq=stats.norm(mean,std)
plt.plot(x,iq.pdf(x),'b')

px=np.arange(0,500,10)
plt.fill_between(px,iq.pdf(px),color='r')

plt.show()