"""
crate_anon/nlp_manager/number.py
===============================================================================
Copyright (C) 2015, University of Cambridge, Department of Psychiatry.
Created by Rudolf Cardinal (rnc1001@cam.ac.uk).
This file is part of CRATE.
CRATE is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
CRATE 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with CRATE. If not, see <https://www.gnu.org/licenses/>.
===============================================================================
**Number conversion functions.**
"""
from typing import Optional
[docs]def to_float(s: str) -> Optional[float]:
"""
Convert a string to a float, or return ``None``.
Before converting:
- strips out commas (as thousands separator); this is not internationalized
well!
- replace Unicode minus and en dash with a hyphen (minus sign)
"""
if s:
s = s.replace(",", "") # comma as thousands separator
s = s.replace("−", "-") # Unicode minus
s = s.replace("–", "-") # en dash
try:
return float(s)
except (TypeError, ValueError):
return None
[docs]def to_pos_float(s: str) -> Optional[float]:
"""
Converts a string to a positive float, by using :func:`to_float` followed
by :func:`abs`. Returns ``None`` on failure.
"""
try:
return abs(to_float(s))
except TypeError: # to_float() returned None
return None