How can I force Python's file.write() to use the same newline format in Windows as in Linux (“\r\n” vs. “\n”)?

Question

I have the simple code:

f = open('out.txt','w')
f.write('line1\n')
f.write('line2')
f.close()

Code runs on windows and gives file size 12 bytes , and linux gives 11 bytes The reason is new line

In linux it's \\n and for win it is \\r\\n

But in my code I specify new line as \\n . The question is how can I make python keep new line as \\n always, and not check the operating system.

Answer 1

You need to open the file in binary mode ie wb instead of w . If you don't, the end of line characters are auto-converted to OS specific ones.

Here is an excerpt from Python reference about open() .

The default is to use text mode, which may convert '\\n' characters to a platform-specific representation on writing and back on reading.

Answer 2

You can still use the textmode and when you print a string, you remove the last character before printing, like this:

f.write("FooBar"[:-1])

Tested with Python 3.4.2.

Edit: This does not work in Python 2.7.

Answer 3

This is an old answer, but the io.open function lets you to specify the line endings:

import io
with io.open('tmpfile', 'w', newline='\r\n') as f:
    f.write(u'foo\nbar\nbaz\n')

From : https://stackoverflow.com/a/2642121/6271889