How to group dataframe rows into list in Pandas Groupby?
Suppose you have a pandas DataFrame consisting of 2 columns and we want to group these columns. In this article, we will discuss about the same. First, let;s create the dataframe.
- Python3
# importing pandas as pdimport pandas as pd # Create the data framedf = pd.DataFrame({'column1': ['A', 'B', 'C', 'A', 'C', 'C', 'B', 'D', 'D', 'A'], 'column2': [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]}) # Print the dataframedf |
Output:
Example #1: We can use groupby() method on column 1 and apply the method to apply a list on every group of pandas DataFrame.
- Python3
# importing pandas as pdimport pandas as pd # Create the data framedf = pd.DataFrame({'column1': ['A', 'B', 'C', 'A', 'C', 'C', 'B', 'D', 'D', 'A'], 'column2': [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]}) # Use groupby method and apply# method on the dataframedf = df.groupby('column1')['column2'].apply(list) # Print the dataframe againdf |
Output:
Example #2: We can use groupby() method on column 1 and agg() method to apply aggregation, consisting of the lambda function, on every group of pandas DataFrame.
- Python3
# importing pandas as pdimport pandas as pd # Create the dataframedf = pd.DataFrame({'column1': ['A', 'B', 'C', 'A', 'C', 'C', 'B', 'D', 'D', 'A'], 'column2': [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]}) # Use groupby method and agg method # with lambda function on the dataframedf = df.groupby('column1').agg({'column2': lambda x: list(x)}) # Print the dataframe againdf |
Output:
Example #3: We can use the groupby() method on column 1 and agg() method to apply the aggregation list, on every group of pandas DataFrame.
- Python3
# importing pandas as pdimport pandas as pd # Create the data framedf = pd.DataFrame({'column1': ['A', 'B', 'C', 'A', 'C', 'C', 'B', 'D', 'D', 'A'], 'column2': [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]}) # Use groupby method and agg method # with list as argument on the dataframedf = df.groupby('column1').agg(list) df |
Output:
Example #4: We can use groupby() method on column 1 and agg() method by passing ‘pd.Series.tolist’ as an argument.
- Python3
# importing pandas as pdimport pandas as pd # Create the data framedf = pd.DataFrame({'column1': ['A', 'B', 'C', 'A', 'C', 'C', 'B', 'D', 'D', 'A'], 'column2': [5, 10, 15, 20, 25, 30, 35, 40, 45, 50]}) # Use groupby method and agg method with# pd.Series.tolist as argument on the dataframedf = df.groupby('column1').agg(pd.Series.tolist) df |
Output:
Last Updated on October 23, 2021 by admin