\r\n or \n notepad editor end line ???

[ajikoe]

Hello,

I use windows notepad editor to write text.

For example I write (in d:\myfile.txt):
Helo
World

If I open it with python:
FName = open(d:\myfile. txt,'r')
h = FName.readlines ()
print h

I get h : ['Helo\n', 'World']

I thought notepad use \r\n to to end the line.

What's wrong with it?

pujo

[Max M]

aj****@gmail.co m wrote:

Hello,

I use windows notepad editor to write text.

For example I write (in d:\myfile.txt):
Helo
World

If I open it with python:
FName = open(d:\myfile. txt,'r')
h = FName.readlines ()
print h

I get h : ['Helo\n', 'World']

I thought notepad use \r\n to to end the line.

What's wrong with it?

Python tries to be clever. Open it in binary mode to avoid it:

FName = open(d:\myfile. txt,'rb')
--

hilsen/regards Max M, Denmark

http://www.mxm.dk/
IT's Mad Science

[Bill Mill]

On 8 Jun 2005 06:24:05 -0700, aj****@gmail.co m <aj****@gmail.c om> wrote:

Hello,

I use windows notepad editor to write text.

For example I write (in d:\myfile.txt):
Helo
World

If I open it with python:
FName = open(d:\myfile. txt,'r')
h = FName.readlines ()
print h

I get h : ['Helo\n', 'World']

I thought notepad use \r\n to to end the line.

What's wrong with it?

On windows, opening a file without 'b' in the file type argument does
some things you might not expect, including changing /r/n to /n. Try:

f = file('d:/deleteme.txt', 'rb')
f.read() 'testing\r\n1\r \n2\r\n3' f = file('d:/deleteme.txt', 'r')
f.read()

'testing\n1\n2\ n3'

Peace
Bill Mill
bill.mill at gmail.com

[ajikoe]

Hello thanks everyone,

It means in windows we should use 'wb' to write and 'rb' to read ?
Am I right?

pujo

[Simon Brunning]

On 8 Jun 2005 06:44:40 -0700, aj****@gmail.co m <aj****@gmail.c om> wrote:

It means in windows we should use 'wb' to write and 'rb' to read ?
Am I right?

It depends what you are trying to do with the file. If you are
processing it as a text file, open it as a text file, and all will be
well:

my_file = open('my_file.t xt')
for line in my_file:
# whatever...

--
Cheers,
Simon B,
si***@brunningo nline.net,
http://www.brunningonline.net/simon/blog/

[Peter Hansen]

aj****@gmail.co m wrote:

It means in windows we should use 'wb' to write and 'rb' to read ?
Am I right?

There is a conceptual difference between "text" files and other files
(which are lumped under the label "binary").

Binary files have any kind of data in them (bytes from 0 to 255) and no
inherent concept of "lines", and thus no line ending sequences.

Text files generally have no control characters except those used to
terminate the lines (lines are by definition sequences of bytes followed
by the line ending sequence). The line ending sequence is
platform-dependent: Linux and most other things use just \n (LineFeed),
while Windows/DOS uses \r\n (CarriageReturn + LineFeed) and the old
MacOS used just \r (CarriageReturn ).

Since the specific line ending used on your platform is rarely important
to you, so long as you are compatible with other applications that use
"text" files (such as Notepad), you should use just "r" and "w" to read
and write files that you consider "text" (and note: it's just a
convention, in your mind... and at some times a given file might be
treated the other way, quite legitimately). Python (actually the
underlying libraries, I believe) will convert the platform-specific line
endings to \n when reading text files, and will convert \n to the proper
line ending sequence for your platform when writing.

If you don't want this conversion, which is unlikely if this is really
just a text file, then and only then do you want to use "rb" and "wb".

So the answer to the question "What should I be using?" depends entirely
on you: if you were interested in seeing the raw bytes that Notepad
wrote, then use "rb". If you want to work with that file as a *text*
file, then use just "r".

Note also the existence of the "U" modifier. Opening a file with "rU"
will read any of the aforementioned line-ending sequences and convert
them to just \n, allowing you to work with text files created on other
platforms. (I don't believe there's a "wU" and conceptually it's sort
of meaningless anyway, so you would just use "w" to write the file out
again.)

-Peter

[ajikoe]

Hello All,

Thanks for the response.

I use mysql and find something strange lately while load text file to
my database table using LINES TERMINATED BY '\r\n',

And I found that mysql think I have '\r\r\n'. this is happened because
in one of my code I use 'w' to write element of string + '\r\n'. now I
understand why this happened.

Actually I prefer to use 'w' and 'r' because the termination of the
line will always '\n'.
By changing mycode to always use 'w' and write element of string +'\n'
instead of +'\r\n' and let my mysql code use LINES TERMINATED '\r\n' I
think solve this problem. :)

pujo

[Greg Ewing]

Peter Hansen wrote:

(I don't believe there's a "wU" and conceptually it's sort
of meaningless anyway,

If we ever get quantum computers, presumably "wU" will
write the newlines in all possible formats simultaneously. ..

--
Greg Ewing, Computer Science Dept,
University of Canterbury,
Christchurch, New Zealand
http://www.cosc.canterbury.ac.nz/~greg

[Fredrik Lundh]

<aj****@gmail.c om> wrote:

It means in windows we should use 'wb' to write and 'rb' to read ?
Am I right?

no.

you should use "wb" to write *binary* files, and "rb" to read *binary*
files.

if you're working with *text* files (that is, files that contain lines of text
separated by line separators), you should use "w" and "r" instead, and
treat a single "\n" as the line separator.

</F>

[Steven D'Aprano]

On Mon, 13 Jun 2005 11:53:25 +0200, Fredrik Lundh wrote:

<aj****@gmail.c om> wrote:

It means in windows we should use 'wb' to write and 'rb' to read ?
Am I right?

no.

you should use "wb" to write *binary* files, and "rb" to read *binary*
files.

if you're working with *text* files (that is, files that contain lines of text
separated by line separators), you should use "w" and "r" instead, and
treat a single "\n" as the line separator.

I get nervous when I read instructions like this. It sounds too much like
voodoo: "Do this, because it works, never mind how or under what
circumstances, just obey or the Things From The Dungeon Dimensions will
suck out your brain!!!"

Sorry Fredrik :-)

When you read a Windows text file using "r" mode, what happens to the \r
immediately before the newline? Do you have to handle it yourself? Or will
Python cleverly suppress it so you don't have to worry about it?

And when you write a text file under Python using "w" mode, will the
people who come along afterwards to edit the file in Notepad curse your
name? Notepad expects \r\n EOL characters, and gets cranky if the \r is
missing.

How does this behaviour differ from "universal newlines"?

--
Steven