[Tutor] failed filter result

[Timo]

Op 06-04-15 om 16:05 schreef Jim Mooney:
> Why did this fail where it did? It failed at listing the result of the
> filter of a word list, but I figured if it failed, it would have done so at
> the filter.
>
>>>> words = open('5desk.txt').readlines()
>>>> k = [word.rstrip for word in words]
Your problem is in the above line. Have this example:

 >>> words = ["foo", "bar", "spam", "eggs"]
 >>> k = [word.rstrip for word in words]
 >>> k
[<built-in method rstrip of str object at 0x7fd1f3cb1538>, <built-in 
method rstrip of str object at 0x7fd1f3cb1880>, <built-in method rstrip 
of str object at 0x7fd1f3cb1148>, <built-in method rstrip of str object 
at 0x7fd1f3cda3e8>]

Looks very similar to your TypeError later on!

Let's see what's wrong:
 >>> "foo".rstrip
<built-in method rstrip of str object at 0x7fd1f3cb1538>

Still the same...

Let's go further:
 >>> "foo".rstrip()
'foo'

Looks much better!
So the problem is you're storing the rstrip function instead of calling 
it and store the result. A big difference.
The fix is very easy, just call rstrip in your list comprehension:
k = [word.rstrip() for word in words]

A little tip: errors like these are easy to debug by printing your 
values. If you printed k before continuing it wouldn't have happened.

Timo

>>>> len(k)
> 61406
>>>> p = filter(lambda word: len(word) > 10, k)
>>>> p
> <filter object at 0x01992F30>
>>>> list(p)
> Traceback (most recent call last):
>    File "<string>", line 301, in runcode
>    File "<interactive input>", line 1, in <module>
>    File "<interactive input>", line 1, in <lambda>
> TypeError: object of type 'builtin_function_or_method' has no len()
>