[Python-ideas] Consider adding clip or clamp function to math

Neil Girdhar mistersheik at gmail.com
Sat Jul 30 17:57:53 EDT 2016

It's common to want to clip (or clamp) a number to a range.  This feature 
is commonly needed for both floating point numbers and integers:


There are a few approaches: 

* use a couple ternary operators 
(e.g. https://github.com/scipy/scipy/pull/5944/files  line 98, which 
generated a lot of discussion)
* use a min/max construction,
* call sorted on a list of the three numbers and pick out the first, or
* use numpy.clip. 

Am I right that there is no *obvious* way to do this?  If so, I suggest 
adding math.clip (or math.clamp) to the standard library that has the 

def clip(number, lower, upper):
    return lower if number < lower else upper if number > upper else number

This would work for non-numeric types so long as the non-numeric types 
support comparison.  It might also be worth adding

assert lower < upper

to catch some bugs.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20160730/9c33ef59/attachment.html>

More information about the Python-ideas mailing list