Opening file problem in wxWindows program

[Fredrik Lundh]

David Ishee wrote:
> I am writing a program that uses wxWindows for the GUI in Windows NT
> with Python 1.5.2. I am trying to open a file and read the contents
> within this program and I'm having trouble. I have the statment:
> 
> usernameFile = open('usernames.dat', 'r')
> 
> However, I get an error message saying:
> 
> TypeError: illegal argument type for built-in operation
> 
> If I create a blank test script with this statement as the only line,
> it works fine. If I enter the statement in the command line of the
> interpreter, it works fine. What could be the problem with using it in
> a script interspersed with wxWindows stuff?
> 
> I have imported these at the top of my script:
> 
> from wxPython.wx import *

note that from-import imports *all* functions and
names from the module:

- maybe wxPython.wx contains an open function?

> from os import *

- maybe os contains an open function?  (it does)

> from string import *

- maybe string contains an open function?

> Any ideas?

just follow the Import Rule:

    "Always use import. 

    As usual, there are a number of exceptions to this rule: 

    1. The Module Documentation Tells You To Use from-import.
    2. You're Importing a Package Component.
    3. You Don't Know the Module Name Before Execution.
    4. You Know Exactly What You're Doing."

    from http://www.pythonware.com/people/fredrik/fyi/fyi06.htm
    (see the webpage for more info)

looks like you broke rule four ;-)

:::

printing the doc string can also help:

>>> print open.__doc__
open(filename[, mode[, buffering]]) -> file object

Open a file.  The mode can be 'r', 'w' or 'a' for reading (default),
writing or appending.  The file will be created if it doesn't exist
when opened for writing or appending; it will be truncated when
opened for writing.  Add a 'b' to the mode for binary files.
Add a '+' to the mode to allow simultaneous reading and writing.
If the buffering argument is given, 0 means unbuffered, 1 means line
buffered, and larger numbers specify the buffer size.

>>> from os import *
>>> print open.__doc__
open(filename, flag [, mode=0777]) -> fd
Open a file (for low level IO).
    
</F>

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