On 01/30/2013 05:43 AM, inshu chauhan wrote:
On Mon, Jan 28, 2013 at 6:05 PM, Dennis Lee Bieber <wlfr...@ix.netcom.com>wrote:
On Mon, 28 Jan 2013 14:31:31 +0100, inshu chauhan
<insidesh...@gmail.com> declaimed the following in
gmane.comp.python.general:
In the code below I am trying to read 2 files f1 and f2 , extract some
data
from them and then trying to write them into a single file that is 'nf'.
import cv
f1 = open(r"Z:\modules\Feature_Vectors_300.arff")
f2 = open(r"Z:\modules\Feature_Vectors_300_Pclass.arff")
nf = open(r"Z:\modules\trial.arff", "w")
for l in f1:
sp = l.split(",")
If you are going to be splitting on commas, you might want to read
up on the csv (comma separate values) module
The csv module has many fuctions but not of much use to me and it makes my
programme slower
if len(sp)!= 12:
continue
else:
Given the apparent block structure, you could drop the
continue/else, and more cleanly just use
Yeah, Thats Right
if len(sp) == 12:
ix = sp[0].strip()
iy = sp[1].strip()
print ix, iy
for s in f2:
It's been mentioned that the indentation is wrong here
I dont know why the indentation is wrong ?
Your for statement is not lined up with the print that precedes it. If
your code were really that way, you'd be getting an indentation error.
So we assume it's because your email editor is mangling the code. Post
in text email, not in html.
st = s.split(",")
csv module again
if len(st)!= 11:
continue
else:
I'm tempted to repeat the comment on reversing the conditional BUT
clas = st[10].strip()
print ix, iy, clas
print >> nf, ix, iy, clas
The indentation of the print statements is not aligned with the
previous assignment -- the effect is the same however as everything
under the else is executed anyway.
But as has also been mentioned, ignoring indentation, the apparent
algorithm you have here is going to process every line of f2 for the
first line of f1 -- and then for later lines in f1 it will find f2 is at
the end of file, and do nothing. If it is supposed to process every line
of f2 for each line of f1, you'll need to rewind f2.
For that I added 'Break' statement as suggested by Chris in above mails.
If you mean to match one line of f1 with one line of f2, you do not
want nested loops. But now you have to define the behavior if one of the
two files is correct length and the other is not? Do you skip both or
read the next line from the wrong length file? And how will you handle
files with different numbers of records.
Yes , actually my Prog was like this :
for l in f1:
sp = l.split(",")
if len(sp)!= 12:
continue
else:
ix = sp[0].strip()
iy = sp[1].strip()
for s in f2:
This is not nested, it's back at the left margin. Or it could be
posting wrong because you're still posting in html, instead of plain
text email.
st = s.split(",")
if len(st)!= 11:
continue
else:
clas = st[10].strip()
print ix, iy, clas
print >> nf, ix, iy, clas
break
f1.close()
f2.close()
nf.close()
I actually dont want nested loops but cant find another way to achieve what
I want, But for these files I am sure that they have equal lengths, thats
why I am taking the risk of using nested loops.
You have that backwards. Because you say you can assume they're the
same length, you don't need the flexibility (and unreadability) of the
nested approach. The zip approach works great, and nested is unnecessary.
. Can you suggest any
different way to go around this problem , which could be flexible and
non-errorneous ?
--
DaveA
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