How to Concatenate Strings from Pandas Groupby Rows?

Concatenating Strings from Rows Using Pandas Groupby

In order to concatenate strings from multiple rows within a groupby operation using Pandas, it is important to understand the structure of the DataFrame and the desired output.

In this case, we have a DataFrame containing text entries grouped by 'name' and 'month' columns. To achieve the desired concatenation, we can use the 'groupby', 'transform', and 'apply' functions.

First, we group the DataFrame by 'name' and 'month':

df[['name','text','month']].groupby(['name','month'])

Next, we apply a lambda expression using 'transform' to join the text entries:

df['text'] = df[['name','text','month']].groupby(['name','month'])['text'].transform(lambda x: ','.join(x))

Finally, we drop duplicate rows and display the result:

df[['name','text','month']].drop_duplicates()

Alternatively, we can use 'apply' to achieve the same result:

df.groupby(['name','month'])['text'].apply(lambda x: ','.join(x)).reset_index()

Another approach, without using a lambda, would be:

df.groupby(['name','month'])['text'].apply(','.join).reset_index()

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