Sylvain Thenault wrote: > Hi there ! > > Can someone explain me the following behaviour ? > >>>> l = [] >>>> 0 in (l is False) > Traceback (most recent call last): > File "<stdin>", line 1, in ? > TypeError: iterable argument required >>>> (0 in l) is False > True >>>> 0 in l is False > False > > > This is really obscur to me... >
>From the language reference (5.9 Comparisons): > comparison ::= or_expr ( comp_operator or_expr )* > comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "<>" | "!=" > | "is" ["not"] | ["not"] "in" > > ...snip... > > Formally, if a, b, c, ..., y, z are expressions and opa, opb, ..., opy > are comparison operators, then a opa b opb c ...y opy z is equivalent > to a opa b and b opb c and ... y opy z, except that each expression is > evaluated at most once. In other words '0 in l is False' is equivalent to '0 in l and l is False'. -- http://mail.python.org/mailman/listinfo/python-list
