DataFrame.
update
Modify in place using non-NA values from another DataFrame. Aligns on indices. There is no return value.
Only left join is implemented, keeping the index and columns of the original object.
How to handle non-NA values for overlapping keys:
True: overwrite original DataFrame’s values with values from other.
False: only update values that are NA in the original DataFrame.
See also
DataFrame.merge
For column(s)-on-columns(s) operations.
DataFrame.join
Join columns of another DataFrame.
DataFrame.hint
Specifies some hint on the current DataFrame.
broadcast
Marks a DataFrame as small enough for use in broadcast joins.
Examples
>>> df = ps.DataFrame({'A': [1, 2, 3], 'B': [400, 500, 600]}, columns=['A', 'B']) >>> new_df = ps.DataFrame({'B': [4, 5, 6], 'C': [7, 8, 9]}, columns=['B', 'C']) >>> df.update(new_df) >>> df.sort_index() A B 0 1 4 1 2 5 2 3 6
The DataFrame’s length does not increase as a result of the update, only values at matching index/column labels are updated.
>>> df = ps.DataFrame({'A': ['a', 'b', 'c'], 'B': ['x', 'y', 'z']}, columns=['A', 'B']) >>> new_df = ps.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']}, columns=['B']) >>> df.update(new_df) >>> df.sort_index() A B 0 a d 1 b e 2 c f
For Series, it’s name attribute must be set.
>>> df = ps.DataFrame({'A': ['a', 'b', 'c'], 'B': ['x', 'y', 'z']}, columns=['A', 'B']) >>> new_column = ps.Series(['d', 'e'], name='B', index=[0, 2]) >>> df.update(new_column) >>> df.sort_index() A B 0 a d 1 b y 2 c e
If other contains None the corresponding values are not updated in the original dataframe.
>>> df = ps.DataFrame({'A': [1, 2, 3], 'B': [400, 500, 600]}, columns=['A', 'B']) >>> new_df = ps.DataFrame({'B': [4, None, 6]}, columns=['B']) >>> df.update(new_df) >>> df.sort_index() A B 0 1 4.0 1 2 500.0 2 3 6.0