[Tutor] creating files with python and a thanks

[Eve Kotyk]

Sheila King wrote:
> 
> On Mon, 18 Feb 2002 03:12:55 +0000, Eve Kotyk <e.kotyk@shaw.ca>  wrote
> about Re: [Tutor] creating files with python and a thanks:
> 
> > > What Python Shell are you using? What operating system?
> >
> > I'm using version 1.5.2 on Linux.
> 
> Well, I'm really flabbergasted. I just logged into my web host, where I
> have a shell account, and they have 1.5.2 on Linux, but it worked for me
> there, as well:
> 
> Python 1.5.2 (#1, Dec 21 2000, 15:29:08)  [GCC egcs-2.91.66
> 19990314/Linux (egcs - on linux-i386
> Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
> >>> def gather_data():
> ...     items = raw_input("Add food item: ")
> ...     portion = input("Enter number of portions: ")
> ...     cal_portion = input("Enter calories per portion: ")
> ...     output = [items, portion, cal_portion]
> ...     f = open('myfile.txt', 'w')
> ...     f.write(str(output))
> ...     f.close()
> ...
> >>> gather_data()
> Add food item: cumquats
> Enter number of portions: 10
> Enter calories per portion: 50
> >>>
> 
> Let's look at that error message you showed before:
> 
> Traceback (innermost last):
>   File "<pyshell#78>", line 1, in ?
>     gather_data()
>   File "<pyshell#75>", line 9, in gather_data
>     f.write(output)
> TypeError: read-only buffer, list
> 
> It says:
>   File "<pyshell#75>", line 9, in gather_data
>     f.write(output)
> TypeError: read-only buffer, list
> 
> Notice how it seems to think that your write statement is
> f.write(output)
> and not f.write(str(output))
> 
> For some reason, it has an old copy of the gather_data function in
> memory, I'm thinking.

You are exactly right!  I just tried it this morning and it worked very
well.  I did not know that the interpreter would keep a previous bit of
code in memory.  
> 
> (Sorry, I didn't catch the importance of that error message previously.)

No problem but could you explain the error message a little?  I assumed
it meant that I had variable elements of a different type (such as a
string and integers) but I tried the code again using only strings and I
still got the same error.  What is a read-only buffer?

E
-- 

ekotyk

http://members.shaw.ca/e.kotyk/virtualstudio.htm