[Tutor] Strings and file saving
Moshe Zadka
Moshe Zadka <moshez@math.huji.ac.il>
Sat, 19 Aug 2000 12:31:02 +0300 (IDT)
On Fri, 18 Aug 2000, Daniel D. Laskey, CPA wrote:
> import sys
> import string
>
> # get the appropriate data file
> in_file = open("data_file","r")
>
> # create the file to export the data to
> out_file = open("junk2.txt","w+")
>
> # read each line in the file
> for line in in_file.readlines():
> if string.find(line,'$')>= 0:
> # # "print line" works well
Instead of:
> # #print line
> a = line
> # # write the new file you created to the file "junk2.txt"
> out_file.write(a)
Why not just:
> out_file.write(line)
(Your problem was that you tried to call out_file.write(a) before you
ever assigned to a: your first line had no '$'. Be thankful, for
otherwise you'd have a nasty bug: a line with a '$' would be printed
from when it was read until the next one was read, once for every line.
IOW, the output for:
1$
2
3$
Would be
1$
1$
3$
Instead of
1$
3$
--
Moshe Zadka <moshez@math.huji.ac.il>
There is no IGLU cabal.
http://advogato.org/person/moshez