6

I have a file which contains a value 2000,00.

But it contains spaces after 2000,00 and empty lines.

I want to remove all the spaces and empty lines, if some one can give some Idea, I ave tried a number of ways but no success.

One method I tired is as below

    # Read lines as a list
fh = open("transfer-out/" + file, "r")
lines = fh.readlines()
fh.close()
# Weed out blank lines with filter
lines = filter(lambda x: not x.isspace(), lines)
# Write "transfer-out/"+file+".txt", "w"
fh = open("transfer-out/"+file, "w")
#fh.write("".join(lines))
# should also work instead of joining the list:
fh.writelines(lines)
fh.close()
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2
  • 1
    Without Python: cat input.txt | egrep -v '^\s*$' > output.txt Commented May 29, 2012 at 6:45
  • 1
    This leaves the spaces after the number. Maybe add a tr: cat input.txt | egrep -v '^\s*$' | tr -d ' ' > output.txt Commented May 29, 2012 at 7:01

5 Answers 5

Reset to default
8

strip() removes leading and trailing whitespace characters.

with open("transfer-out/" + file, "r") as f:
    for line in f:
        cleanedLine = line.strip()
        if cleanedLine: # is not empty
            print(cleanedLine)

Then you can redirect the script into a file python clean_number.py > file.txt, for example.

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2 Comments

Factor out those repeated strip() calls, and you're onto a winner. :-)
It's just the name of the directory containing the file named file.
4

Another one with list comprehension:

clean_lines = []
with open("transfer-out/" + file, "r") as f:
    lines = f.readlines()
    clean_lines = [l.strip() for l in lines if l.strip()]

with open("transfer-out/"+file, "w") as f:
    f.writelines('\n'.join(clean_lines))
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1 Comment

You should add a join: f.writelines('\n'.join(clean_lines)).
2

Change your 'lines' line to use the following generator and it should do the trick.

lines = (line.strip() for line in fh.readlines() if len(line.strip()))
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1 Comment

if len(line.strip()) can be replaced with if line.strip()
1

This should work as you wish:

file(filename_out, "w").write(file(filename_in).read().strip())

EDIT: Although previous code works in python 2.x, it does not work python 3 (see @gnibbler comment) For both version use this:

open(filename_out, "w").write(open(filename_in).read().strip())
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11 Comments

I think you meant open not file here.
No. I meant file. I prefer file, but according to doc (docs.python.org/library/functions.html?highlight=file#file) open is prefferable :-(
@BurhanKhalid, file is a deprecated synonym for open. It exists in Python2 because open is a strange name for subclassing file or using with isinstance. It no longer exists in Python3
@Jiri what is filename_out and filename_in ?
@gnibbler Oh, yes, I am using 2.x most of the time and I have not realized this! I think it's time to use open instead of file.
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1

Functional one :)

import string
from itertools import ifilter, imap

print '\n'.join(ifilter(None, imap(string.strip, open('data.txt'))))
# for big files use manual loop over lines instead of join

Usage:

$ yes "2000,00  " | head -n 100000 > data.txt
$ python -c "print '\n'*100000" >> data.txt
$ wc -l data.txt 
200001 data.txt
$ python filt.py > output.txt
$ wc -l output.txt 
100000 output.txt
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2 Comments

I am sorry I am to dumb to read your code ! I have to accesss my file from a folder and removing spaces and empty lines from it !
and yeh one more thing write data back to the same file

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