<div dir="auto"><div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Apr 1, 2019, 8:54 PM Steven D'Aprano <<a href="mailto:steve@pearwood.info">steve@pearwood.info</a>> wrote:</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
The point I am making is not that we must not ever support multiple affixes, but that we shouldn't rush that decision. Let's pick the low-hanging fruit, and get some real-world experience with the function before deciding how to handle the multiple affix case.<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">There are exactly two methods of strings that deal specifically with affixes currently. Startswith and endswith. Both of those allow specifying multiple affixes. That's pretty strong real-world experience, and breaking the symmetry for no reason is merely confusing. Especially since the consistency would be obviously as commonly useful.</div><div dir="auto"><br></div><div dir="auto">Now look, the sky won't fall if a single-affix-only method is added. For that matter, it won't if nothing is added. In fact, the single affix version makes it a little bit easier to write a custom function handling multiple affixes.</div><div dir="auto"><br></div><div dir="auto">And the sky won't fall if the remove-just-one semantics are used rather than remove-from-class.</div><div dir="auto"><br></div><div dir="auto">But adding methods with sneakily helpful capabilities often helps users greatly. A lot of folks in this thread didn't even know about passing a tuple to str.startswith() a few days ago. I'm pretty sure that capability was added by Raymond, who has an amazingly good sense of what little tricks can prove really powerful. Apologies to a different developer if it wasn't him, but congrats and thanks to you if so.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Somebody (I won't name names, but they know who they are) wrote to me off-list some time ago and accused me of being arrogant and thinking I know more than everyone else. Well perhaps I am, but I'm not so arrogant as to think that I can choose the right behaviour for clashing affixes for other people when my own use-cases don't have clashing affixes.<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">That could be me... Unless it's someone else :-). I think my intent was a bit different than you characterize, but I'm very guilty of presuming too much also. So mea culpa.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
> Sure, but I've often wanted to do something like "strip off a prefix<br>
> of http:// or https://", or something else that doesn't have a<br>
> semantic that's known to the stdlib.<br>
<br>
I presume there's a reason you aren't using urllib.parse and you just need a string without the leading scheme. If you're doing further parsing, the stdlib has the right batteries for that.<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">I know there are lots of specialized string manipulations in the STDLIB. Yeah, I could use os.path.splitext, and os.path.split, and urllib.parse.something, and lots of other things I rarely use. A lot of us like to manipulate strings in generically stringy ways.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">But not until we had a couple of releases of experience with them:<br>
<br>
<a href="https://docs.python.org/2.7/library/stdtypes.html#str.endswith" rel="noreferrer noreferrer" target="_blank">https://docs.python.org/2.7/library/stdtypes.html#l.endswith</a></blockquote></div></div><div dir="auto"><br></div><div dir="auto">Ok. Fair point. I used Python 2.4 without the multiple affix option.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Here's a partial list of English prefixes that somebody doing text <br>
processing might want to remove to get at the root word:<br>
<br>
a an ante anti auto circum co com con contra contro de dis<br>
en ex extra hyper il im in ir inter intra intro macro micro<br>
mono non omni post pre pro sub sym syn tele un uni up<br>
<br>
I count fourteen clashes:<br>
<br>
a: an ante anti<br>
an: ante anti<br>
co: com con contra contro<br>
ex: extra<br>
in: inter intra intro<br>
un: uni<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">This seems like a good argument for remove-all-from-class. :-)</div><div dir="auto"><br></div><div dir="auto"> stem = word.lstrip(prefix_tup)</div><div dir="auto"><br></div><div dir="auto">But the we really need 'word.porter_stemmer()' as a built-in method.</div></div>