getting rid of EOL character ?

[John Machin]

On 27/04/2007 11:19 PM, Michael Hoffman wrote:
> stef wrote:
>> hello,
>>
>> In the previous language I used,
>> when reading a line by readline, the EOL character was removed.

Very interesting; how did you distinguish between EOF and an empty line? 
Did you need to call an isEOF() method before each read?

>>
>> Now I'm reading a text-file with CR+LF at the end of each line,
>>    Datafile = open(filename,'r')    line = Datafile.readline()
>>
>> now this gives an extra empty line
>>    print line
>>
>> and what I expect that should be correct, remove CR+LF,
>> gives me one character too much removed
>>    print line[,-2]

Stef, that would give you a syntax error. I presume that you meant to 
type line[:-2]

>>
>> while this gives what I need ???
>>    print line[,-1]
>>
>> Is it correct that the 2 characters CR+LF are converted to 1 character ?

In text mode (the default), whatever is the line ending on your platform 
is converted to a single "newline" '\n' which is the same as LF.

Using line[:-1] is NOT recommended, as the last line in your file may 
not be terminated, and in that case you would lose the last data character.

>> Is there a more automatic way to remove the EOL from the string ?
> 
> line = line.rstrip("\r\n") should take care of it. If you leave out the 
> parameter, it will strip out all whitespace at the end of the line, 
> which is what I do in most cases.

If you want *exactly* what is in the line, use line.rstrip('\n') -- this 
will remove only the trailing newline (if it exists).

If you want to strip all trailing whitespace, use line.rstrip() as 
Michael suggested.

Michael, note carefully that line.rstrip('\r\n') removes instances of 
'\r' OR '\n' -- the arg is a set of characters to be removed, not a 
suffix to be removed. In Stef's situation, it "works" only by accident. 
Using that would not always give you the correct answer -- e.g. if your 
(Windows) file had a line ending in CR CR LF [I've seen stranger].

HTH,
John