Histogram of one field wrt another in pandas python

问题

I am trying to plot a histogram distribution of one column with respect to another. For example, if the dataframe columns are ['count','age'], then I want to plot the total counts in each age group. Suppose in

age: 0-10 -> total count was 20

age: 10-20 -> total count was 10

age: 20-30 -> ... etc

I tried groupby('age') and than plotting histogram but it didn't work.

Thanks.

Update

Here is some of my data

df.head()
   age    count
0   65  2417.86
1   65  4173.50
2   65  3549.16
3   65   509.07
4   65     0.00

Also, df.plot( x='age', y='count', kind='hist') shows

回答1:

Ok,if I understand correctly, you want a weighted histogram

import pylab as plt
import pandas as pd
np = pd.np

df = pd.DataFrame( {'age':np.random.normal( 50,10,300).astype(int),
                    'counts':1000*np.random.random(300)} ) # test data
#df.head()
#   age      counts
#0   38  797.174450
#1   36  402.171434
#2   49  894.218420
#3   66  841.786623
#4   51  597.040259

df.hist('age',weights=df['counts'] )
plt.ylabel('counts')
plt.show()

yields the figure

来源：https://stackoverflow.com/questions/31780893/histogram-of-one-field-wrt-another-in-pandas-python