Can't delete "\r\n" from a string

Question

I have a string like this:

la lala 135 1039 921\r\n

And I can't remove the \r\n.

Initially this string was a bytes object but then I converted it to string

I tried with .strip("\r\n") and with .replace("\r\n", "") but nothing...

Solution 1

The issue is that the string contains a literal backslash followed by a character. Normally, when written into a string such as .strip("\r\n") these are interpreted as escape sequences, with "\r" representing a carriage return (0x0D in the ASCII table) and "\n" representing a line feed (0x0A).

Because Python interprets a backslash as the beginning of an escape sequence, you need to follow it by another backslash to signify that you mean a literal backslash. Therefore, the calls need to be .strip("\\r\\n") and .replace("\\r\\n", "").

Note: you really don't want to use .strip() here as it affects a lot more than just the end of the string as it will remove backslashes and the letters "r" and "n" from the string. .replace() is a little better here in that it will match the whole string and replace it, but it will match \r\n in the middle of the string too, not just the end. The most straight-forward way to remove the sequence is the conditional given below.

You can see the list of escape sequences Python supports in the String and Byte Literals subsection of the Lexical Analysis section in the Python Language Reference.

For what it's worth, I would not use .strip() to remove the sequence. .strip() removes all characters in the string (it treats the string as a set, rather than a pattern match). .replace() would be a better choice, or simply using slice notation to remove the trailing "\\r\\n" off the string when you detect it's present:

if s.endswith("\\r\\n"):
    s = s[:-4]

Solution 2

>>> my_string = "la lala 135 1039 921\r\n"
>>> my_string.rstrip()
'la lala 135 1039 921'

Alternate solution with just slicing off the end, which works better with the bytes->string situation:

>>> my_string = b"la lala 135 1039 921\r\n"
>>> my_string = my_string.decode("utf-8")
>>> my_string = my_string[0:-2]
>>> my_string
'la lala 135 1039 921'

Or hell, even a regex solution, which works better:

re.sub(r'\r\n', '', my_string)

Solution 3

'\r\n' is also a standard line delimiter for .splitlines(), so this can also work.

>>> s = "la lala 135 1039 921\r\n"
>>> type(s)
<class 'str'>
>>> t = ''.join(s.splitlines())
>>> t
'la lala 135 1039 921'
>>> type(t)
<class 'str'>