[Python-ideas] Add list.join() please

Barry Scott barry at barrys-emacs.org
Wed Jan 30 13:31:09 EST 2019

> On 30 Jan 2019, at 10:07, Jamesie Pic <jpic at yourlabs.org> wrote:
> On Wed, Jan 30, 2019 at 7:03 AM Robert Vanden Eynde
> <robertve92 at gmail.com> wrote:
>>> Raises an error. Why should:
>>> “”.join([2, “2”]) not raise an error as well?
>> I agree
> What do you think could be the developer intent when they do
> ",".join([2, "2']) ?
> If the intent is clearly to assemble a string, as it looks like, then
> I don't find any disadvantage to automate this task for them.

The intent is not clear. How is the 2 to be formatted?

I fixed a nasty bug recently where a join of a list of strings contained a non-string in some cases.
If the str(bad_value) had been the default I would not have been able to track this down from the
traceback in a few minutes.

I'm -1 on this idea as it would hide bugs in my experience.


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