Martin v. Löwis added the comment: This is not a bug. extend is a procedure with a side effect: the "self" object (i.e. "a" in your example) is modified.
By convention, procedures return None in Python, as opposed to functions, which have no side effect but return a result. This is to avoid code like def combine(a, b): return a.extend(b) a = ... b = ... c = combine(a,b) If extend would return the "self" list, then people may think that they get a fresh, new list, and then wonder why a is modified. IOW: your bug report is actually invalid; the result that print shows is exactly the right result that extend returns. ---------- nosy: +loewis resolution: -> invalid status: open -> closed _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue15614> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
