This was proposed about four years ago, Here is a link to the first post in the thread:
https://mail.python.org/pipermail/python-ideas/2016-July/041262.html Discussion spilled over into the following month, here's the first post following: https://mail.python.org/pipermail/python-ideas/2016-August/041276.html As I recall, there was some positive support but it ran out of steam because nobody could agree on how to handle NANs even though the IEEE-754 standard tells us how to handle them *wink* See my responses at the time re NANs here: https://mail.python.org/pipermail/python-ideas/2016-August/041439.html https://mail.python.org/pipermail/python-ideas/2016-August/041400.html https://mail.python.org/pipermail/python-ideas/2016-August/041396.html Bottom line is that passing a NAN as the lower or upper bound should treat it as equivalent to "unbounded", that is, equivalent to ±∞. The beauty of that is that it can be implemented without explicitly testing for NANs, which involves unnecessary conversions to float, and may even raise an exception. Here is the version I use: def clamp(value, lower, upper): """Clamp value to the closed interval lower...upper. The limits lower and upper can be set to None to mean -∞ and +∞ respectively. """ if not (lower is None or upper is None): if lower > upper: raise ValueError('lower must be <= to upper') if lower == upper is not None: return lower if lower is not None and value < lower: value = lower elif upper is not None and value > upper: value = upper return value Features: * uses None as a convenient alias for unbounded; * treats NANs according to the standard; * requires no explicit conversion to float or testing for NANs; * so this will work with Fractions and Decimals. By the way, using "minmax" as the name would be inappropriate as that typically has other meanings, either to return the minimum and maximum in a single call, or in the sense of minimizing the maximum value of some function or process. -- Steven _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/NIQOL3DG3F3PIH234R24EVRMJ7LZYSZL/ Code of Conduct: http://python.org/psf/codeofconduct/
