2015-09-05 5:01 GMT+02:00 Guido van Rossum <gu...@python.org>: > And I'm ready to accept it. I'll wait until Tuesday night (Monday's a > holiday in the US) in case anything unforeseen comes up, but this is really > the Last Call for this PEP.
String concatenation is inefficient in Python because strings are immutable. There is a micro-optimization which tried to reduce the bad performances of a+b, but it's better to avoid it. Python replaces >'abc' 'def'< with a single string >'abcdef'<. It's done by the parser, there is no overhead at runtime. PEP 498 allows to write >'abc' f'string'< which is replaced with >'abc' 'string'.__format__()< whereas str+str is a bad practice. I would prefer to force users to write an explicit '+' to remind them that there are more efficient ways to concatenate strings like ''.join((str1, str2)) or putting the first string in the f-string: >f'abcstring'<. Section in the PEP: https://www.python.org/dev/pepsstring/pep-0498/#concatenating-strings Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
