Merge a list of dataframes to create one dataframe

Question

I have a list of 18 data frames:

dfList = [df1, df2, df3, df4, df5, df6.....df18]

All of the data frames have a common id column so it’s easy to join them each together with pd.merge 2 at a time. Is there a way to join them all at once so that dfList comes back as a single dataframe?

Asked By: Josh

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Source

Answer 1

I think you need concat, but first set index of each DataFrame by common column:

dfs = [df.set_index('id') for df in dfList]
print pd.concat(dfs, axis=1)

If need join by merge:

from functools import reduce
df = reduce(lambda df1,df2: pd.merge(df1,df2,on='id'), dfList)

Answered By: jezrael

Merge a list of dataframes to create one dataframe

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