Terminology: "reference" versus "pointer"
Steven D'Aprano
steve at pearwood.info
Mon Sep 14 12:59:36 EDT 2015
On Mon, 14 Sep 2015 01:23 pm, Akira Li wrote:
> Steven D'Aprano <steve at pearwood.info> writes:
>
>> On Mon, 14 Sep 2015 11:22 am, Akira Li wrote:
>>> Look at the last example:
>>> http://thread.gmane.org/gmane.comp.python.general/782626/focus=782704
>>
>>
>> I'm afraid that page is broken in my browser. Can you not summarise, or
>> link to the specific message? I may be able to use another browser in a
>> day or two, but hopefully the discussion will have moved on by then.
>
> https://mail.python.org/pipermail/python-list/2015-September/696631.html
Thanks. You mean this example?
lst = [range(1, 3) for _ in range(3)]
a = [lst[0], lst[0]]
b = [lst[1], lst[2]]
I don't see what's difficult about this example. Here's a simple ASCII
drawing:
lst --------> [ range-object-1 , range-object-2 , range-object-3 ]
a ----------> [ range-object-1 , range-object-1 ]
b ----------> [ range-object-2 , range-object-3 ]
Trying to draw an arrow diagram using text is not my idea of a good time,
but I'll give it a go. Requires a monospaced font and an email client that
won't reflow the text:
+-----+------+
| | | <--------------------------- a
+--|--+---|--+
| |
| |
V |
+-----+ <-+ +----+
|range| <---------------|- |<------------ lst
+-----+ +----+
+-----------|- |
+-----+ | +----+
+-> |range| <---+ +------|- |
| +-----+ | +----+
| |
| +-----+ |
| |range| <--------+
| +-----+
| ^
+-|-+ |
| | |
+---+ |
| -|----+
+---+
^
|
+------------------------------------------- b
Out of the two, I know which one I prefer.
--
Steven
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