Question

I stumbled across something that is not a problem, but something rather puzzling. I am copying a xml file myxml.xml to myxml_copy.xml and the file size of the output file is bigger. I don’t understand why this is so. Does this have anything to do with file encoding?

Anyway, the code I am using (although it is fairly trivial):

from xml.dom.minidom import parseString
import sys

def parseXml():
    data = open(in_filename,'r').read()
    return data


try:
    in_filename = sys.argv[1]
    out_filename = sys.argv[2]

    out_file = open(out_filename,'w')
    out_file.write(parseXml())
    out_file.close()
except Exception,e:
    print "usage: python copy.py <in_file> <out_file>"
    print "Error",e

---

NOTE: I am not looking for a way to copy a file. I will be modifying the original xml file later (cutting and pasting different parts of it).

Answer 1

I think the problem is that the mode you open the file with needs to be rb and not just r and wb instead of w. (means – with binary mode)

When it’s rb – strings like \r\n will stay this way, but when the mode is r – they will become \n.

In short – just change the lines:

data = open(in_filename,'r').read()
out_file = open(out_filename,'w')

to

data = open(in_filename,'rb').read()
out_file = open(out_filename,'wb')

Did that help?