Armando Serrano Lombillo a écrit : > On Oct 29, 3:20 pm, Bruno Desthuilliers <bruno. > [EMAIL PROTECTED]> wrote: >> Armando Serrano Lombillo a écrit : >> >>> Why does Python give an error when I try to do this: >>>>>> len(object=[1,2]) >>> Traceback (most recent call last): >>> File "<pyshell#40>", line 1, in <module> >>> len(object=[1,2]) >>> TypeError: len() takes no keyword arguments >>> but not when I use a "normal" function: >>>>>> def my_len(object): >>> return len(object) >>>>>> my_len(object=[1,2]) >>> 2 >> In the second case, the name of the argument *is* 'object'. Which is not >> the case for the builtin len (which, fwiw, has type >> 'builtin_function_or_method', not 'function', so inspect.getargspec >> couldn't tell me more). > > so that's the point, built-in functions don't behave as normal > functions.
>> <ot> >> While we're at it, you should avoid using builtin's names for >> identifiers - here, using 'object' as the arg name shadows the builtin >> 'object' class). >> </ot> > > As Duncan points out, I was using the name object because it's what > you get when you type help(len) That what I thought. But anyway, you're not the only person reading this newsgroup, and there are a couple gotchas that are worth pointing out for those who don't know yet. >(or in the calltips, or in). Anyway, I > don't think there's any harm in overriding a builtin name in such a > small scope In this specific case, possibly - because there are few chances you need to get at the builtin object type here. Still, it's better to avoid shadowing builtin names IMHO - if only for readability. -- http://mail.python.org/mailman/listinfo/python-list
