Python Forum

I hope you are all having a good day. I want to know why my merge below is returning the key error that is stated below my code. Any help would be appreciated.

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
%matplotlib inline

dict1={'eggs':(1,7,44,76,23,56,22,21,20,11,12,81),'month':('jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec')}

dict2={'bread':(22,43,17,9,22,16,71,82,24,34,54,45),'months':('jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec')}

df1=pd.DataFrame(dict1)

df2=pd.DataFrame(dict2)

df1.columns.values[1]='months'

pd.merge(left=df1,right=df2,on='months')

KeyError: 'months'

Your example works for me. Perhaps you forgot to run line 15 (that renames month column as months column), so there was no 'months' key in df1 and merge failed?

The code works perfectly with this output

Output:
 	eggs 	months 	bread
0 	1 	jan 	22
1 	7 	feb 	43
2 	44 	mar 	17
3 	76 	apr 	9
4 	23 	may 	22
5 	56 	jun 	16
6 	22 	jul 	71
7 	21 	aug 	82
8 	20 	sep 	24
9 	11 	oct 	34
10 	12 	nov 	54
11 	81 	dec 	45

It appears that the error you get is because you have not renamed the month column in first dataframe to months
Check out this pandas tutorial to know more