[Python-Dev] Usage of += on strings in loops in stdlib (original) (raw)

MRAB python at mrabarnett.plus.com
Wed Feb 13 00:20:01 CET 2013

On 2013-02-12 21:44, Antoine Pitrou wrote:

On Tue, 12 Feb 2013 16:40:38 -0500 Ned Batchelder <ned at nedbatchelder.com> wrote:

But the only reason "".join() is a Python idiom in the first place is because it was "the fast way" to do what everyone initially coded as "s += ...". Just because we all learned a long time ago that joining was the fast way to build a string doesn't mean that "".join() is the clean idiomatic way to do it. It's idiomatic because strings are immutable (by design, not because of an optimization detail) and therefore concatenation has to imply building a new string from scratch. Tuples are much like immutable lists; sets were added, and then frozensets; should we be adding mutable strings too (a bit like C#'s StringBuilder)? (Just wondering...)

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