Use list name as string

[Vincent Davis]

"The problem is you seem to be thinking in terms of objects having names.
They don't.  Names have objects."I agree this is my problem. This is not
correct terminology then?
The name of the object is anobject

Let me give another example and let me know if I am just beating a dead
horse.

In my current script I have may print statements to verify I am manipulating
my list as I hope.
I have many lines like;

print 'alist', alist

I need to print the names so I know what I am looking at on the output.
It would be nice if I could define fuction that did this
def lp(thelist):
    "magic occurs"

Then I could just type

lp(alist)

note I am entering the name which has an object that is a list. I am not
entering [1,3,5,7]
and it would

print 'alist' alist

Does it not seem reasonable to what to do this.


Vincent Davis
720-301-3003


On Wed, Feb 4, 2009 at 7:55 PM, Rhodri James <rhodri at wildebst.demon.co.uk>wrote:

> On Thu, 05 Feb 2009 01:36:17 -0000, Vincent Davis <
> vincent at vincentdavis.net> wrote:
>
>  if I start with
>> M = [1,3,5,7]
>> M is [1,3,5,7]
>> This seems one way, as [1,3,5,7] is not M in the sense that there is
>> no operation I can preform on [1,3,5,7] and get M back. Other than
>> asking/testing M==[1,3,5,7]
>>
>
> Correct.  If you actually try that, you get this:
>
> Python 2.5.2 (r252:60911, May  7 2008, 15:21:12)
> [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>
>> M = [1,3,5,7]
>>>> M is [1,3,5,7]
>>>>
>>> False
>
> This isn't just me being funny with your suggested syntax, it's
> making an important point: the second [1,3,5,7] is an entirely
> different object to the list we named M, it just happens to
> contain the same data.
>
>  This seems fine to me. but when I savedata(M) it seems I should be
>> able to refer to both [1,3,5,7] and "M", "I mean I did just type it
>> why type it again)
>> My argument comes down to; we use M so we don't have to type
>> [1,3,5,7], I realize that this is in part because we might not no what
>> M will be.
>>
>
> That's an oversimplification, and you're battering away well past the
> point where it works.  In any language, not just Python.
>
>  This is starting to sound like double talk on my part, I have only
>> been programing in python for 2 weeks so my credibility is only that
>> of an outside that MAY have a reasonable way of thinking of this or at
>> least a feature I would like.
>>
>
> The problem is you seem to be thinking in terms of objects having names.
> They don't.  Names have objects.
>
> What I mean by that is that when you type "M = [1,3,5,7]", you are saying
> "when I say 'M', substitute in this list (not just one that looks like it,
> this exact list".  When you type "N = M", similarly you get the name N
> bound to the same exact list; if you then type "N[1] = 2" and print out
> M, it'll show up as [1,2,5,7] -- it's still the same list under both names.
> In effect (to oversimplify more than a bit), Python looks up the name
> in a dictionary to get the object it represents.
>
> The reverse lookup doesn't exist, largely because it isn't unique.  Our
> [1,3,5,7] list has no idea what names, if any, refer to it, and in all
> but the most trivial cases the information isn't really meaningful.
> Suppose that we did have a "getvariablename" function, what would you
> expect the following code to do?
>
> def f(thing):
>    print getvariablename(thing)
>
> m = [1,3,5,7]
> for n in m:
>    f(n)
>
>
> Should it say "n" for all of them?  Or "['n', 'thing']", since 'thing'
> is after all a perfectly valid name for it?
>
> Then what about this:
>
> for i in range(len(m)):
>    f(m[i])
>
>
> Should it say "m[i]" for all of them, or "m[0]" "m[1]" and so on, or
> what?
>
>  by the way what is "**kwargs" I can't find any documentation on this?
>>
>
> http://docs.python.org/tutorial/controlflow.html#keyword-arguments
>
> In a function definition, "**name" mops up all the keyword arguments
> to the function that aren't explicit formal parameters into a
> dictionary called "name", indexed by keyword.  "kwargs" seems to be
> the traditional name to use.  So:
>
>  def demo(action, **kwargs):
>>>>
>>> ...   print kwargs
> ...
>
>> demo(action="dummy", text="wombats are go")
>>>>
>>> {'text': 'wombats are go'}
>
>
> You can also use it the other way round to expand a dictionary into
> keyword parameters to a function call:
>
>  myargs = { 'action': 'avoid', 'where': 'Camelot', 'because': 'it is a
>>>> silly place' }
>>>> demo(**myargs)
>>>>
>>> {'because': 'it is a silly place', 'where': 'Camelot'}
>
> --
> Rhodri James *-* Wildebeeste Herder to the Masses
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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