Splitting Pandas Dataframe Based on Column Values Using Groupby
In Python, it is possible to split a Pandas dataframe into multiple dataframes based on the values in a specific column. This technique is commonly utilized to create separate dataframes for each unique category or group within the column.
For instance, consider the following dataframe with a column named "ZZ":
df = N0_YLDF ZZ MAT 0 6.286333 2 11.669069 1 6.317000 6 11.669069 2 6.324889 6 11.516454 3 6.320667 5 11.516454 4 6.325556 5 11.516454 5 6.359000 6 11.516454 6 6.359000 6 11.516454 7 6.361111 7 11.516454 8 6.360778 7 11.516454 9 6.361111 6 11.516454
The goal is to split this dataframe into four new dataframes, with each dataframe containing the rows where "ZZ" has a specific value: 2, 5, 6, and 7. To achieve this, we can leverage the Pandas "groupby" function.
gb = df.groupby('ZZ') [gb.get_group(x) for x in gb.groups]
The "groupby" function creates a GroupBy object, which groups the dataframe rows based on the values in the specified column ("ZZ" in this case). Each unique value of "ZZ" becomes a group within the GroupBy object.
The subsequent line uses a list comprehension to iterate over the groups and retrieve each group as a separate dataframe. The "get_group" method is called with each group's name (i.e., the unique values of "ZZ") to extract the corresponding dataframe.
As a result, this code generates four new dataframes, each representing a subset of the original dataframe rows that share the same value in the "ZZ" column.
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