On Thursday, February 13, 2014 7:26:48 PM UTC-8, Ned Batchelder wrote: > On 2/13/14 9:45 PM, forman.si...@gmail.com wrote: > > > For the record I wasn't worried about the performance. ;-) > > > > > > It was for Tkinter event strings not markup tags. > > > > > > I'm glad this was the time winner! > > > > > > "key and key[0] == '<' and key[-1] == '>'" > > > > > > > > > Cheers to the folks who did the timings (and saved me from the trouble!) > > > > > > Last but not least... s[::len(s)-1] omg!!? ;-D > > > > > > > If you aren't worried about performance, why are you choosing your code > > based on which is the fastest? There are other characteristics > > (clarity, flexibility, robustness, ...) that could be more useful.
I guess I'm taking the word "worried" a little too seriously. Back story: I am hoping to contribute to IDLE and am reading the code as a first step. I came across that line of code (BTW, I was wrong: it is NOT processing Tkinter event strings but rather special "<pyshell#...> entries" in linecache.cache [1]) and had to resist the urge to change it to something more readable (to me.) But when I thought about it I wasn't able to discern if any of the new versions would actually be enough of an improvement to justify changing it. To be clear: I have no intention of modifying the IDLE codebase just for fairly trivial points like this one line. The most satisfying (to me) of the possibilities is "if key and key[0] == '<' and key[-1] == '>':" in the dimensions, if you will, of readability and, uh, unsurprising-ness, and so I was pleased to learn that that was also the fastest. (FWIW, it seems to me that whoever wrote that line was influenced by shell programming. It's a shell sort of a trick to my eye.) When writing Python code I *do* value "clarity, flexibility, robustness" and almost never worry about performance unless something is actually slow in a way that affects something.. Warm regards, ~Simon [1] http://hg.python.org/cpython/file/3a1db0d2747e/Lib/idlelib/PyShell.py#l117 -- https://mail.python.org/mailman/listinfo/python-list
