problem with str()

[kyosohma at gmail.com]

On Mar 15, 2:49 pm, "7stud" <bbxx789_0... at yahoo.com> wrote:
> I can't get the str() method to work in the following code(the last
> line produces an error):
>
> ============
> class test:
>         """class test"""
>         def __init__(self):
>                 """I am init func!"""
>                 self.num = 10
>                 self.num2 = 20
>         def someFunc(self):
>                 """I am someFunc in test!"""
>                 print "hello"
>
> obj = test()
> obj.someFunc()
> names = dir(obj)
> print names
>
> methodList = [str for str in names if callable(getattr(obj, str))]
> print methodList
>
> x = getattr(obj, methodList[0]).__doc__
> print x
> print type(x)
> print str(getattr(obj, methodList[0]).__doc__)
> ===========
>
> Here is the output:
>
> $ python test1.py
> hello
> ['__doc__', '__init__', '__module__', 'num', 'num2', 'someFunc']
> ['__init__', 'someFunc']
> I am init func!
> <type 'str'>
> Traceback (most recent call last):
>   File "test1.py", line 23, in ?
>     print str(getattr(obj, methodList[0]).__doc__)
> TypeError: 'str' object is not callable
>
> This is part of some code in Diving Into Python,Chapter 4.  In case a
> function doesn't have a __doc__ string, and therefore __doc__ returns
> None, the code needs to convert each __doc__ to a string so that the
> result is guaranteed to be a string.

Your string comprehension over wrote the str built-in method, turning
it into a variable. If you just type "str" (without the quotes) into
the interpreter, it'll spit out 'someFunc'. Thus, you cannot use str
as the iterator in your code:

methodList = [str for str in names if callable(getattr(obj, str))]

instead, do something like this:

methodList = [i for i in names if callable(getattr(obj, i))]

Have fun!

Mike