En Wed, 07 Mar 2007 15:21:57 -0300, Laurent Pointal <[EMAIL PROTECTED]> escribió:
> Gabriel Genellina wrote: > >> En Wed, 07 Mar 2007 12:53:43 -0300, Laurent Pointal >> <[EMAIL PROTECTED]> escribió: >> >>> Why does Python allow generator expression parenthesis to be mixed with >>> function call parenthesis when there is only one parameter ? >Beginners generally know about list-comprehensions and associate the > syntax "x for x in asequence" to a list expression. I'm not sure that But list comprehensions have [] around... When you don't see the [], you should think "this is something different"... > reading a "f(i for i in range(20))" they understand that they are dealing > with a different object kind. Exactly. > If function f start by a if len(myparameter)... > TypeError: len() of unsized object > > If function f goes among its parameter with "for x in myparameter" more > than > once, other loops goes throught an empty loop. Then he thinks "Something is wrong!", and reads some Python books, or asks here, and somebody will point him to the Python Tutorial, section 9.11: http://docs.python.org/tut/node11.html#SECTION00111100000000000000000 >>> IMHO this should be forbidden, usage must not be different when there >>> is only one parameter and when there are more parameters. If you want to review the original discussion on how to spell a generator expression (called "accumulator display" by that time) see http://mail.python.org/pipermail/python-dev/2003-October/038868.html -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
