pandas.errors.ChainedAssignmentError#
- exception pandas.errors.ChainedAssignmentError[source]#
Warning raised when trying to set using chained assignment.
When the
mode.copy_on_write
option is enabled, chained assignment can never work. In such a situation, we are always setting into a temporary object that is the result of an indexing operation (getitem), which under Copy-on-Write always behaves as a copy. Thus, assigning through a chain can never update the original Series or DataFrame.For more information on view vs. copy, see the user guide.
Examples
>>> pd.options.mode.copy_on_write = True >>> df = pd.DataFrame({'A': [1, 1, 1, 2, 2]}, columns=['A']) >>> df["A"][0:3] = 10 ... # ChainedAssignmentError: ... >>> pd.options.mode.copy_on_write = False