How can I remove a trailing newline?

Question

What is the Python equivalent of Perl\'s chomp function, which removes the last character of a string if it is a newline?

Answer 1

It looks like there is not a perfect analog for perl's chomp. In particular, rstrip cannot handle multi-character newline delimiters like \r\n. However, splitlines does as pointed out here. Following my answer on a different question, you can combine join and splitlines to remove/replace all newlines from a string s:

''.join(s.splitlines())

The following removes exactly one trailing newline (as chomp would, I believe). Passing True as the keepends argument to splitlines retain the delimiters. Then, splitlines is called again to remove the delimiters on just the last "line":

def chomp(s):
    if len(s):
        lines = s.splitlines(True)
        last = lines.pop()
        return ''.join(lines + last.splitlines())
    else:
        return ''