On 1/29/2019 7:12 PM, MRAB wrote:
On 2019-01-29 23:30, Terry Reedy wrote:
On 1/28/2019 8:40 PM, Jamesie Pic wrote:
> 0. os.path.join takes *args
Since at least 1 path is required, the signature is join(path, *paths).
I presume that this is the Python version of the Unix version of the
system call that it wraps.. The hidden argument is os.sep. It is
equivalent to os.sep.join((path,)+paths) (though one would not write it
this way).
1. str.join takes a list argument,
This premise behind the (repeated) request is a false. str.joins
arguments are a string (the joiner) and an *iterable of strings*, which
is an abstract subclass of the abstract concept 'iterable'. And only a
small fraction of lists are lists of strings and therefore iterables of
strings.
One the examples given was writing:
>>> '/'.join('some', 'path')
To me, this suggests that what the OP _really_ wants is for str.join to
accept multiple arguments, much as os.path.join does.
I thought that there would be a problem with that because currently the
single argument is an iterable, and you wouldn't want to iterate the
first argument of '/'.join('some', 'path').
However, both min and max will accept either a single argument that's
iterated over or multiple arguments that are not, so there's a precedent
there.
I have done things like this in private code, but it makes for messy
signatures. The doc pretends that min has two signatures, given in the
docstring:
min(iterable, *[, default=obj, key=func]) -> value
min(arg1, arg2, *args, *[, key=func]) -> value
I believe that the actual signature is the uninformative min(*args,
**kwargs). The arg form, without key, is the original. If min were
being written today, I don't think it would be included.
--
Terry Jan Reedy
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