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Saving variable value to a file does not work!!!!

Steve Holden sholden at holdenweb.com
Sun Sep 30 12:52:11 EDT 2001 
"Husam" <husalwan at sci.kun.nl> wrote in message
news:3BB74291.CB898293 at sci.kun.nl...
> Hi friends,
> Im  a newbie and trying to save the value of variable 'counter' to a
> file, but it does not work.
> The code Im usig is:
>
>
> for line in lines:                # I'm reading from file: test2.txt.
> One of it's lines contain: ID 5.
>     string.split(line)

Unforunately the line above does not alter the "line" variable. Maybe what
you need is

    line = string.split(line)

or it's method-based alternative (good in 2.x):

    line = line.split()

However, once you have split the line, you cannot then continue to treat is
as a string, since you will have transformed it into an array of strings.
The next two statements should therefore be changed...

>     if line[0:2]=='ID':
>         counter=int(line[3])

    if line[0] == 'ID':
        counter = int(line[1])

However, the code as you have written it appears to work because you are
treating line as a string throughout, so you might equally prefer to simpy
remove the string.split(line) call, which does nothing because you don't
assign the result.

>         output=open('test2.txt','a') # Hier Im opening the same file for
> append.
>         output.write(counter +1)            # This is the trouble making
> line!
> output.close()
>
>
> The error message I get when this code is run:
>
> Traceback (innermost last):
>   File "./script.py", line 23, in ?
>     output.write(counter+1)
> TypeError: read-only buffer, int
>
This error message appears because what you are trying to write is not a
string:

>>> output = open("deleteme.txt", "a")
>>> output.write(5+1)
Traceback (innermost last):
  File "<pyshell#1>", line 1, in ?
    output.write(5+1)
TypeError: read-only character buffer, int

The following should work:

    output.write(str(counter+1))

>>> output.write(str(5+1))
>>>

Hope this helps.

regards
 Steve
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