[Python-ideas] "any" and "all" support multiple arguments

[Terry Reedy]

On 8/1/2017 9:01 AM, Louie Lu wrote:
> Hi all,
> 
> In "min" and "max" builtin-func, it support two style of args:
> 
>      min(...)
>          min(iterable, *[, default=obj, key=func]) -> value
>          min(arg1, arg2, *args, *[, key=func]) -> value

To me, two APIs is a nuisance.  For one thing, default has to be keyword 
only and not just optional.  Compare with sum:

 >>> sum((2,3,4),5)
14

 >>> min((2,3,4),5)  # Py3
Traceback (most recent call last):
   File "<pyshell#7>", line 1, in <module>
     min((2,3,4),5)
TypeError: '<' not supported between instances of 'int' and 'tuple'

 >>> min((2,3,4),5)  # Py2
5
 >>> min(5, (2,3,4))
5

I believe that a version of the second was in original Python (and at 
least in 1.3) whereas the first was added later, likely with the new 
iterator protocol (2.2).  In any case,  with *unpacking in displays, the 
second is no longer needed.

 >>> min(4,3, *[1,2])
1
 >>> min((4,3, *[1,2]))
1

If I am correct, perhaps the doc for max and min in 
https://docs.python.org/3/library/functions.html#max
should mention that the 2nd is derived from the original syntax, kept 
for back compatibility (rather than a new innovation, to be imitated).

I would rather get rid of the exceptional case than emulate it.

> But for "any" and "all", it only support iterable:
> 
>      all(iterable, /)
>          Return True if bool(x) is True for all values x in the iterable.

As Nick pointed out, this is standard now.

 >>> list((1,2,3))
[1, 2, 3]
 >>> list(1,2,3)
Traceback (most recent call last):
   File "<pyshell#4>", line 1, in <module>
     list(1,2,3)
TypeError: list() takes at most 1 argument (3 given)

-- 
Terry Jan Reedy