> ****************************************************************
> 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):
print len(thing)
else:
print len(str(thing))
#print 1
or whatever sort of result you expect here.
Or you can give it a best-effort:
for thing in a:
try:
print len(thing)
except TypeError:
print 1
and let exception-handling deal with it for you.
Just a few ideas,
-tkc
--
http://mail.python.org/mailman/listinfo/python-list
