On 05/12/2015 15:43, Terry Reedy wrote:
On 12/5/2015 9:41 AM, D'Arcy J.M. Cain wrote:
On Sat, 5 Dec 2015 13:56:47 +0100
Robin Koch <robin.k...@t-online.de> wrote:
x += y works. (Well, it should.)
It does, even on objects other than numbers.
x = "abc"
y = "def"
x += y
x
'abcdef'
x++ doesn't.
No but it's just a special case of the above.
x = 1
x += 1
x
2
Apple is removing the ++ and -- pre- and post- increment and decrement
operators from Swift 3.0 as redundant with += 1.
https://github.com/apple/swift-evolution/blob/master/proposals/0004-remove-pre-post-inc-decrement.md
The following section is a good summary of why they were never added to
Python, and should not be.
'''
Disadvantages of These Operators
1. These operators increase the burden to learn Swift as a first
programming language - or any other case where you don't already know
these operators from a different language.
2. Their expressive advantage is minimal - x++ is not much shorter than
x += 1.
The latter is not the same. Some of the differences are:
* ++ and -- are often inside inside expressions and return values
(unlike x+=1 in Python)
* x++ and x-- return the /current/ value of x, unlike x+=1 even if it
were to return a value; it would be the new value
* x+=1 requires you to hard-code the value 1, but ++ is not necessarily
stepping by 1. You can imagine ++ stepping something to its next value.
However, if ++ and -- are only used as statements, then why not simply
map them to x+=1? In Python, that would need to be x++ and x-- as ++x or
--x have existing meanings.
--
Bartc
--
https://mail.python.org/mailman/listinfo/python-list
