On Tue, Mar 31, 2020 at 4:20 AM Joao S. O. Bueno <jsbueno@python.org.br> wrote:
Hi Andrew -
I made my previous post before reading your first answer.
So, anyway, what we have is that for a "mutable string like object" one is free to build his wrapper - StringIO based or not - put it on pypi, and remember calling `str()` on it before having it leave your code.
Thank you for the lengthy reply anyway.
That said, anyone could tell about small, efficient, well maintained "mutable string" classes on Pypi?
There's a vast difference between "mutable string" and "string builder". The OP was talking about this kind of thing: buf = "" for i in range(50000): buf += "foo" print(buf) And then suggested using a StringIO for that purpose. But if you're going to change your API, just use a list: buf = [] for i in range(50000): buf.append("foo") buf = "".join(buf) print(buf) So if you really want a drop-in replacement, don't build it around StringIO, build it around list. class StringBuilder: def __init__(self): self.data = [] def __iadd__(self, s): self.data.append(s) def __str__(self): return "".join(self.data) This is going to outperform anything based on StringIO fairly easily, plus it's way WAY simpler. But this is *not* a mutable string. It's a string builder. If you want a mutable string, first figure out exactly what mutations you need, and what performance you are willing to accept. ChrisA