Re: increment/decrement operators

From	Ian Kelly <ian.g.kelly@gmail.com>
Newsgroups	comp.lang.python
Subject	Re: increment/decrement operators
Date	2015-12-07 17:24 -0700
Message-ID	<mailman.42.1449534294.12405.python-list@python.org> (permalink)
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On Dec 5, 2015 10:21 AM, "BartC" <bc@freeuk.com> wrote:

>

>

> 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

Since x+=1 is not an expression, this is moot.

> * 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.

Note that x+=1 does not necessarily have to mean stepping by 1 either. You
could even do something like x+=5 to mean skip the next four values and
step x to the value after that.

> 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.

I think a better question is if they're only going to be statements, then
why bother adding them? x++ doesn't give you anything you can't get from
x+=1, so why commit to supporting the extra syntax?

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Thread

increment/decrement operators Tony van der Hoff <tony@vanderhoff.org> - 2015-12-05 12:40 +0000
  Re: increment/decrement operators Robin Koch <robin.koch@t-online.de> - 2015-12-05 13:56 +0100
    Re: increment/decrement operators Tony van der Hoff <tony@vanderhoff.org> - 2015-12-05 14:14 +0000
    Re: increment/decrement operators "D'Arcy J.M. Cain" <darcy@VybeNetworks.com> - 2015-12-05 09:41 -0500
    Re: increment/decrement operators Terry Reedy <tjreedy@udel.edu> - 2015-12-05 10:43 -0500
      Re: increment/decrement operators BartC <bc@freeuk.com> - 2015-12-05 17:18 +0000
        Re: increment/decrement operators Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-07 17:24 -0700

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