chython/chython/interop/_pandas.py at master · chython/chython

Repository navigation

# -*- coding: utf-8 -*-

# This file is part of chython.

# chython is free software; you can redistribute it and/or modify

# it under the terms of the GNU Lesser General Public License as published by

# the Free Software Foundation; either version 3 of the License, or

# (at your option) any later version.

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

# GNU Lesser General Public License for more details.

# You should have received a copy of the GNU Lesser General Public License

# along with this program; if not, see <https://www.gnu.org/licenses/>.

"""

Teach pandas that a container is one value and not a list of atoms.

`pandas.io.formats.printing.is_sequence(x)` asks whether `iter(x)` and `len(x)` both work, and for a

`MoleculeContainer` they do, so a column of molecules would render as a column of atom-number lists.

The predicate here is the whole of `is_container`, so a container that later grows `__len__` cannot

regress this silently.

"""

__all__ = ['patch_pandas']

_patched = False

def patch_pandas():

"""

Render chython containers as single values in pandas output rather than as lists of atoms.

Idempotent: patching twice would wrap the wrapper, so a second call returns.

"""

global _patched

if _patched:

return

_patched = True

from pandas.io.formats import printing

from pandas.io.formats.printing import is_sequence

from . import is_container

def patched(obj):

# `is_container` first: two `isinstance` calls, where `is_sequence` builds an iterator

return False if is_container(obj) else is_sequence(obj)

printing.is_sequence = patched