Michael Hartl wrote: > I warmly recommend downloading Peter Norvig's Python utilities file > (http://aima.cs.berkeley.edu/python/utils.py) and putting it on your > Python path. (E.g., in bash, put a line like > > export PYTHONPATH="/path/to/utilities_directory" > > in your .bashrc file.) The utils.py file defines many useful > functions, including the ones you want: > > # def every(predicate, seq): > # """True if every element of seq satisfies predicate. > # Ex: every(callable, [min, max]) ==> 1; every(callable, [min, 3]) > ==> 0 > # """ > # for x in seq: > # if not predicate(x): return False > # return True > # > # def some(predicate, seq): > # """If some element x of seq satisfies predicate(x), return > predicate(x). > # Ex: some(callable, [min, 3]) ==> 1; some(callable, [2, 3]) ==> 0 > # """ > # for x in seq: > # px = predicate(x) > # if px: return px > # return False >
What an interesting mixed API design. The every() function returns True or False. However the "some" function returns the FIRST fat result if it's true in the non-boolean sense, otherwise False. Looks like there could theoretically be scope for two pairs of functions, one returning strictly True/False, and the other pair emulating chains of Python 'and's and 'or's. I.e. False or 0 or [] evaluates to [] 0 or 5 or 6 evaluates to 5 42 and None and True evaluates to None 4 and 5 and 6 evaluates to 6 All very nice, but useful? Dubious. PEPpable? Nah, two thumbs down. Diez's advice to the OP is sound: if it bothers you that much, mine the net for, or write, routines that do exactly what you want, and put them in your own utilities module. -- http://mail.python.org/mailman/listinfo/python-list
