How to Remove a Trailing Newline in Python

Using rstrip Method

The str.rstrip() method returns a copy of the string with trailing characters removed. For example,

#!/usr/bin/python3

s = "\nab c\r\n"

# str.rstrip([chars])
n = s.rstrip()
# n = s.lstrip()
# n = s.strip()
print('{!r}'.format(n))

n = s.rstrip("\n")
print('{!r}'.format(n))

'\nab c'
'\nab c\r'

If omitted or None, the chars argument defaults to removing whitespace.

In addition to rstrip(), there are also the methods strip() and lstrip().

Using regex Module

You can use regex() module to remove a trailing newline, it really simple. For example,

#!/usr/bin/python3

# Import module
import re

s = "\nab c\r\n"

# trailing newline chars
n = re.sub(r'[\n\r]+$', '', s)
print('{!r}'.format(n))

# newline chars everywhere
n = re.sub(r'[\n\r]+', '', s)
print('{!r}'.format(n))

# only 1-2 trailing
n = re.sub(r'[\n\r]{1,2}', '', s)
print('{!r}'.format(n))

'\nab c'
'ab c'
'ab c'

Using translate Method

The str.translate() method returns a copy of the string in which each character has been mapped through the given translation table.

#!/usr/bin/python3

# Import module
import string

s = "\nab c\r\n"

n = s.translate({ord(c): None for c in string.whitespace})
print('{!r}'.format(n))

'abc'

Using splitlines Method

The str.splitlines() method returns a list of the lines in the string, breaking at line boundaries.

#!/usr/bin/python3

s = "\nab c\r\n"

n = ''.join(s.splitlines())
# n = ''.join(s.split())
print('{!r}'.format(n))

'ab c'

This method splits on the following line boundaries:

\n
Line Feed
\r
Carriage Return
\r\n
Carriage Return + Line Feed
\v or \x0b
Line Tabulation
\f or \x0c
Form Feed
\x1c
File Separator
\x1d
Group Separator
\x1e
Record Separator
\x85
Next Line (C1 Control Code)
\u2028
Line Separator
\u2029
Paragraph Separator