Make a copy of this object's indices and data. When ``deep=True`` (default), a new object will be created with a copy of the calling object's data and indices. Modifications to the data or indices of the copy will not be reflected in the original object (see notes below). When ``deep=False``, a new object will be created without copying the calling object's data or index (only references to the data and index are copied). Any changes to the data of the original will be reflected in the shallow copy (and vice versa). .. note:: The ``deep=False`` behaviour as described above will change in pandas 3.0. `Copy-on-Write <https://pandas.pydata.org/docs/dev/user_guide/copy_on_write.html>`__ will be enabled by default, which means that the "shallow" copy is that is returned with ``deep=False`` will still avoid making an eager copy, but changes to the data of the original will *no* longer be reflected in the shallow copy (or vice versa). Instead, it makes use of a lazy (deferred) copy mechanism that will copy the data only when any changes to the original or shallow copy is made. You can already get the future behavior and improvements through enabling copy on write ``pd.options.mode.copy_on_write = True``