Lukasz Lukasz - 27 days ago 5
Python Question

Plotting a dataframe as both a 'hist' and 'kde' on the same plot

I have a pandas

dataframe
with user information. I would like to plot the age of users as both a
kind='kde'
and on
kind='hist'
on the same plot. At the moment I am able to have the two separate plots. The dataframe resembles:

member_df=
user_id Age
1 23
2 34
3 63
4 18
5 53
...


using

ax1 = plt.subplot2grid((2,3), (0,0))
member_df.Age.plot(kind='kde', xlim=[16, 100])
ax1.set_xlabel('Age')

ax2 = plt.subplot2grid((2,3), (0,1))
member_df.Age.plot(kind='hist', bins=40)
ax2.set_xlabel('Age')

ax3 = ...


I understand that the
kind='kde'
will give me frequencies for the y-axis whereas
kind='kde'
will give a cumulative distribution, but is there a way to combine both and have the y-axis be represented by the frequencies?

Answer

pd.DataFrame.plot() returns the ax it is plotting to. You can reuse this for other plots.

Try:

ax = member_df.Age.plot(kind='kde')
member_df.Age.plot(kind='hist', bins=40, ax=ax)
ax.set_xlabel('Age')

example
I plot hist first to put in background
Also, I put kde on secondary_y axis

import pandas as pd
import numpy as np


np.random.seed([3,1415])
df = pd.DataFrame(np.random.randn(100, 2), columns=list('ab'))

ax = df.a.plot(kind='hist')
df.a.plot(kind='kde', ax=ax, secondary_y=True)

enter image description here


response to comment
using subplot2grid. just reuse ax1

import pandas as pd
import numpy as np

ax1 = plt.subplot2grid((2,3), (0,0))

np.random.seed([3,1415])
df = pd.DataFrame(np.random.randn(100, 2), columns=list('ab'))

df.a.plot(kind='hist', ax=ax1)
df.a.plot(kind='kde', ax=ax1, secondary_y=True)

enter image description here

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