Tim Chase wrote:
>> ****************************************************************
>> a = ['spam!', 1, ['Brie', 'Roquefort', 'Pol le Veq'], [1, 2, 3]]
>>
>> As an exercise, write a loop that traverses the previous list and
>> prints the length of each element. What happens if you send an
>> integer to len?
>> ****************************************************************
>>
>> for i in a:
>> print len(a[i])
>>
>> will not do.
>> the list has str, int, list, list.
>> I am expecting the output to be 1, 1, 3, 3 which are the number of
>> elements of each element of a, someone might think the result should
>> be 4, 3, 3 which is len(a), len(a[2]), len(a[3]) but how can I do both
>> thoughts with a loop?
>
>
> Well, first off, you've got a strange indexing going on there: a[i]
> requires that the index be an integer. You likely *mean*
>
> for thing in a:
> print len(thing)
>
> If so, you can just wrap it in a check:
>
> for thing in a:
> if "__len__" in dir(thing):
I think the one and only one way to express this is
if hasattr(thing, "__len__"):
--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095
http://www.jamesstroud.com/
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