Re: Writing to a certain line?
- From: bruno at modulix <onurb@xxxxxxxxxxx>
- Date: Tue, 06 Jun 2006 10:49:08 +0200
Tommy B wrote:
I was wondering if there was a way to take a txt file and, while
keeping most of it, replace only one line.
<meta>
This is a FAQ (while I don't know if it's in the FAQ !-), and is in no
way a Python problem. FWIW, this is also CS101...
</meta>
You can't do this in place with a text file (would be possible with a
fixed-length binary format).
The canonical way to do so - whatever the language, is to write the
modified version in a new file, then replace the old one.
import os
old = open("/path/to/file.txt", "r")
new = open("/path/to/new.txt", "w")
for line in old:
if line.strip() == "Bob 62"
line = line.replace("62", "66")
new.write(line)
old.close()
new.close()
os.rename("/path/to/new.txt", "/path/to/file.txt")
If you have to do this kind of operation frequently and don't care about
files being human-readable, you may be better using some lightweight
database system (berkeley, sqlite,...) or any other existing lib that'll
take care of gory details.
Else - if you want/need to stick to human readable flat text files - at
least write a solid librairy handling this, so you can keep client code
free of technical cruft.
HTH
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xxxxxxxxxxx'.split('@')])"
.
- Follow-Ups:
- Re: Writing to a certain line?
- From: Tommy B
- Re: Writing to a certain line?
- From: gene tani
- Re: Writing to a certain line?
- From: Rene Pijlman
- Re: Writing to a certain line?
- From: Fredrik Lundh
- Re: Writing to a certain line?
- References:
- Writing to a certain line?
- From: Tommy B
- Writing to a certain line?
- Prev by Date: Checking var is a number?
- Next by Date: Re: the most efficient method of adding elements to the list
- Previous by thread: Re: Writing to a certain line?
- Next by thread: Re: Writing to a certain line?
- Index(es):
Relevant Pages
|
