On Fri, 8 May 2020 at 14:16, Steven D'Aprano <st...@pearwood.info> wrote:
> On Thu, May 07, 2020 at 03:43:23PM +0200, Dominik Vilsmeier wrote: > > > >We could define this .EQ. operate as *sequence equality*, defined very > > >roughly as: > > > > > > def .EQ. (a, b): > > > return len(a) == len(b) and all(x==y for x, y in zip(a, b)) > > > > > But why do we even need a new operator when this simple function does > > the job (at least for sized iterables)? > > Maybe it doesn't need to be an operator, but operators do have a big > advantage over functions: > > http://neopythonic.blogspot.com/2019/03/why-operators-are-useful.html > > On the other hand we only have a limited number of short symbols > available in ASCII, and using words as operators reduces that benefit. > > > > How common is it to compare two objects where you cannot determine > > whether one or the other is a tuple or a list already from the > > surrounding context? In the end these objects must come from somewhere > > and usually functions declare either list or tuple as their return type. > > Never, because we can always determine whether something is a list or > tuple by inspecting it with type() or isinstance(). But that's missing > the point! I don't care and don't want to know if it is a tuple or > list, I only care if it quacks like a sequence of some kind. > > The use-case for this is for when you want to compare elements without > regard to the type of the container they are in. This is a duck-typing > sequence element-by-element equality test. > > If you have ever written something like any of these: > > list(a) == list(b) > tuple(a) == b > ''.join(chars) == mystring > all(x==y for x,y in zip(a, b)) > That looks like a zip call that could do with checking its input or strict=True! > then this proposed operator might be just what you need. > > > > -- > 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/2375P7QI66QZ4VCL7SJRUFU3AXOMVIJZ/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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