[Tutor] TypeError: 'str' object is not callable

[Alan Gauld]

On 15/05/2021 15:13, me wrote:
> Hello,
> 
> I'm on my very first steps with python and I have a problem where I don't see, 
> what's wrong.
> 
> This is the code:
> -----<snip>-----------
> #!/usr/bin/env python3
> import glob
> 
> class foo:

This is a *terrible* name for a class. Use a noun that describes
what it represents! In this case it is a wrapper around a
string which represents a path.

Not very useful, but at least calling it Path would be
more descriptive.


>     def __init__(self, path):
>         self.path = path
>     def path(self):
>         return self.path

The issue here is the order on which the code is executed.
When you first run the code the class definition is executed which
defines a method called self.path and another called self.__init__.

When you create a new instance of the class self.init is executed.
What it does is create a new binding of self.path to the string
variable path. The old binding to the method is now lost.

> def main():
>     hs = []
>     drives = glob.glob('/dev/sd?') 
>     for d in drives:
>         print(d)
>         hs.append(foo(d))

Each instance of foo overwrites the method with the string d.

>     for e in hs:
>         print(e.path())
>
>

So now, when you call e.path() you are trying to call the string.

A simple solution to this is to use a different name for
the attribute path. A common trick is to put an underscore
in front:

def __init__(self.path):
    self._path = path

def path(self):
    return self._path

A more general option is to use an article prefix such as 'the':

def __init__(self.path):
    self.thePath = path

def path(self):
    return self.thePath


HTH
-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos