Comparing two dataframe values in python

Question

I have two dataframes df1['LicId'] and df2['LicId'].

df1['LicId'] will always have one value

    LicId
0   abc1234

However df2['LicId'] will have several Ids

    LicId
0   abc1234
1   xyz2345

My task is to compare df1['LicId'] with df2['LicId'] and execute the code only if there is a match between two.

I have tried:

if df1['LicId'][0]==df2['LicId'][0]:
    remaining code

However, this will check only for abc1234 - It has to check for all the Index values of df2. Later, I may also have xyz2345 in df1.

Can someone let me know how to handle this?

Sorry but your question is very poorly worded. I have no idea what you want to do. — elelias
– elelias, Commented Aug 24, 2016 at 15:34
Sorry about that - How to compare the value of one dataframe with the values of other dataframe? I have to execute my code only these two values are equal. — Prasad
– Prasad, Commented Aug 24, 2016 at 15:47
Can you post samples of your dataframes along with the desired output? — user2285236
– user2285236, Commented Aug 24, 2016 at 15:47
if df2 is relatively small in size, you can just check if df1.LicId[0] in df2.LicId.values: ..., or just use merge: if len(df1.merge(df2)): ... — Anzel
– Anzel, Commented Aug 24, 2016 at 16:32

ragesz · Accepted Answer · 2016-08-24 16:26:39Z

1

You can match values with isin():

df1 = pd.DataFrame({'LicId':['abc1234', 'a', 'b']})
df2 = pd.DataFrame({'LicId':['abc1234', 'xyz2345', 'a', 'c']})

df1:

     LicId
0  abc1234
1        a
2        b

df2:

     LicId
0  abc1234
1  xyz2345
2        a
3        c

Matching values:

if len(df2.loc[df2['LicId'].isin(df1['LicId'])]) > 0:
    print(df2.loc[df2['LicId'].isin(df1['LicId'])])
    #remaining code

Output:

     LicId
0  abc1234
2        a

answered Aug 24, 2016 at 16:17

ragesz

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1 Comment

As a side note isin will require both index & column labels matching for dataframe