I wrote: > all() can be terminated at the first false element. For very long > sequences this has important performance benefits. Besides, it makes > all(seq,pred) the equivalent of pred(seq[0]) and pred(seq[1]) and > pred(seq[2]) and ...
then, Martin v. Löwis wrote: > > And so does the version with generator expressions: Alex' expression > will also terminate with the first false statement; it is equivalent > to some_objects[0]==0 and some_objects[1]==0 and ... and Alex Martelli wrote: > Of course it can -- in both formulations. genexp's are also computed > "as needed", only one item at a time: you appear to imply they don't, > maybe you're confusing them with list comprehensions. What I'm asking > is, what are the ADVANTAGES of the pred form, that make it worth > paying the conceptual cost of having "two obvious ways" to do one > task. > >> all(seq,pred) the equivalent of pred(seq[0]) and pred(seq[1]) and >> pred(seq[2]) and ... > > ...and also the equivalent of all(pred(s) for s in seq) -- which is > exactly my problem: I don't like redundant good ways of expressing > identical tasks. The genexp will often be more compact, whenever the > 'pred' requires a def, a lambda, or something like > operator.attrgetter, anyway. Oops! Right you are. I was a bit too quick after seeing the use of map() proposed. --eric _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
