writing on file not until the end

Alessandro zasaconsulting at gmail.com
Mon May 25 10:30:01 CEST 2009


On May 25, 8:38 am, Peter Otten <__pete... at web.de> wrote:
> Alexzive wrote:
> > I am a newby with python. I wrote the following code to extract a text
> > from a file and write it to another file:
>
> > linestring = open(path, 'r').read() #read all the inp file in
> > linestring
>
> > i=linestring.index("*NODE")
> > i=linestring.index("E",i)
> > e=linestring.index("*",i+10)
> > textN = linestring[i+2:e-1] # crop the ELement+nodes list
> > Nfile = open("N.txt", "w")
> > Nfile.write(textN)
>
> > unfortunately when I check N.txt some lines are missing (it only crop
> > until "57, 0.231749688431, 0.0405121944142" but I espect the final
> > line to be "242, 0.2979675, 0.224605896461". I check textN and it has
> > all the lines until "242..")
>
> > when I try Nfile.write(textN) again it writes some more lines but
> > still not all!
> > what is wrong whit this?
>
> Do you check the contents of the resulting file by feeding it to another
> program?
>
> > 53, 0.170973146505, 0.0466686190136
> > 57, 0.231749688431, 0.0405121944142
> > t60, 0.250420691759, 0.0399644155193
> > 58, 0.234883810317, 0.0488399925217
> > 61, 0.2666025, 0.03541845
>
> There's a "t" at the start of the line after the last line you claim to see,
> so maybe your input file is corrupt and your reader stumbles over that line.
>
> Peter

Thank you all for replying.

- yes, I oversaw the "t" at "60, 0.250420691759, 0.0399644155193". I
then removed it for the following tests
- changing from "e-1" to "e" apparently solved the problem, BUT I then
realized it was just because a second access to the file (still open)
seems to be the real solution --> after Nfile.close() e retrying with
"e" instead of "e-1" the problem is still there.
- I also tryied to inizialize e and i to zero --> nothing changes
- until now, the only solution which works is to repeat the code while
the file is still open, which means a quite redundant code:

linestring = open(path, 'r').read()
i=linestring.index("*NODE")
i=linestring.index("E",i)
e=linestring.index("*",i+10)
textN = linestring[i+2:e-1] # crop the ELement+nodes list
Nfile = open("N.txt", "w")
Nfile.write(textN)

linestring = open(path, 'r').read()
i=linestring.index("*NODE")
i=linestring.index("E",i)
e=linestring.index("*",i+10)
textN = linestring[i+2:e-1] # crop the ELement+nodes list
Nfile = open("N.txt", "w")
Nfile.write(textN)

Alex



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