Variable Variable

[Tanteauguri]

Hi List, is there in python a variable variable like in PHP ($$var)?

What I want to do is something like that:

pc=["a","b","c"]

for i in pc:
i = anyclass()

a.shutdown()
b.update()


Any Ideas?

Many Thanks, m

[Leif K-Brooks]

Re: Variable Variable

Tanteauguri wrote:[color=blue]
> Hi List, is there in python a variable variable like in PHP ($$var)?
>
> What I want to do is something like that:
>
> pc=["a","b","c"]
>
> for i in pc:
> i = anyclass()
>
> a.shutdown()
> b.update()[/color]

Use a dictionary:

stuff = {}
pc = ['a', 'b', 'c']

for i in pc:
stuff[i] = anyclass()

stuff['a'].shutdown()
stuff['b'].update()

[Premshree Pillai]

Re: Variable Variable

On Sat, 19 Mar 2005 04:35:47 -0500, Leif K-Brooks <eurleif@ecritt ers.biz> wrote:[color=blue]
> Tanteauguri wrote:[color=green]
> > Hi List, is there in python a variable variable like in PHP ($$var)?
> >
> > What I want to do is something like that:
> >
> > pc=["a","b","c"]
> >
> > for i in pc:
> > i = anyclass()
> >
> > a.shutdown()
> > b.update()[/color]
>
> Use a dictionary:
>
> stuff = {}
> pc = ['a', 'b', 'c'][/color]

I think what he wants to do is basically hold object names in a tuple
list, and then call the methods on those objects (while iterating or
whatever).
[color=blue]
>
> for i in pc:
> stuff[i] = anyclass()
>
> stuff['a'].shutdown()
> stuff['b'].update()
> --
> http://mail.python.org/mailman/listinfo/python-list
>[/color]


--
Premshree Pillai

http://www.livejournal.com/users/premshree/

[Kay Schluehr]

Re: Variable Variable


Tanteauguri wrote:[color=blue]
> Hi List, is there in python a variable variable like in PHP ($$var)?
>
> What I want to do is something like that:
>
> pc=["a","b","c"]
>
> for i in pc:
> i = anyclass()
>
> a.shutdown()
> b.update()
>
>
> Any Ideas?[/color]

def seq(n,cls,*args ,**kw):
"create a sequence of n objects of type cls."
return [cls(*args,**kw) for i in range(n)]
[color=blue][color=green][color=darkred]
>>> a,b,c = seq(3,anyclass)
>>> a.shutdown()
>>> b.update()[/color][/color][/color]

Regards Kay

[Cameron Laird]

Re: Variable Variable

In article <1111229201.840 663.141530@g14g 2000cwa.googleg roups.com>,
Kay Schluehr <kay.schluehr@g mx.net> wrote:[color=blue]
>
>Tanteauguri wrote:[color=green]
>> Hi List, is there in python a variable variable like in PHP ($$var)?
>>
>> What I want to do is something like that:
>>
>> pc=["a","b","c"]
>>
>> for i in pc:
>> i = anyclass()
>>
>> a.shutdown()
>> b.update()
>>
>>
>> Any Ideas?[/color]
>
>def seq(n,cls,*args ,**kw):
> "create a sequence of n objects of type cls."
> return [cls(*args,**kw) for i in range(n)]
>[color=green][color=darkred]
>>>> a,b,c = seq(3,anyclass)
>>>> a.shutdown()
>>>> b.update()[/color][/color]
>
>Regards Kay
>[/color]

I'm going to make this explicit: the PHP idiom is a defect.
Yes, I know that's good style among top PHP practitioners,
but, from all I know, it's simply a bad habit. The advice to
use a dictionary is on target.

[Bruno Desthuilliers]

Re: Variable Variable

Tanteauguri a écrit :[color=blue]
> Hi List, is there in python a variable variable like in PHP ($$var)?[/color]

Hopefully, no.

See other answers in that thread for pythonic idioms.

[Kay Schluehr]

Re: Variable Variable

> I'm going to make this explicit: the PHP idiom is a defect.[color=blue]
> Yes, I know that's good style among top PHP practitioners,
> but, from all I know, it's simply a bad habit. The advice to
> use a dictionary is on target.[/color]

I tried to like it the whole last hour ;-)

I reconstructed the formal structure of $$var from a PHP Web-tutorial
though i do not have any experience with the language.

This is what i got:

$ =
<Name> ---> <Var> --------------> <Var>x<String >
| |
$ | # | $ o q' o proj2
| |
V V
<Var> ----- f ------> <Var>
| |
| # | =
| V
+-----------------> <Var>x<String >
=

In the diagram $ is an operator that creates a var from a name, = is an
operator that binds a string to a var and q' drops quotations from a
string to get an name. The function f is an implied isomorphism. It
represents the equivalence of $$a and $b, where $a = "b".

Personally I could live with that, but the diagram is a bit special
because of the restriction of the = operation. I do not know if PHP
supports this operational view by enabling iterations: $a, $$a, $$$a
.... ?

After all I can also live without that in Python...

Regards Kay

[Diez B. Roggisch]

Re: Variable Variable

>[color=blue]
> Personally I could live with that, but the diagram is a bit special
> because of the restriction of the = operation. I do not know if PHP
> supports this operational view by enabling iterations: $a, $$a, $$$a
> ... ?[/color]

It does.
--
Regards,

Diez B. Roggisch

[MikeyG]

Re: Variable Variable

Premshree Pillai wrote:[color=blue]
> On Sat, 19 Mar 2005 04:35:47 -0500, Leif K-Brooks <eurleif@ecritt ers.biz> wrote:
>[color=green]
>>Tanteauguri wrote:
>>[color=darkred]
>>>Hi List, is there in python a variable variable like in PHP ($$var)?
>>>
>>>What I want to do is something like that:
>>>
>>>pc=["a","b","c"]
>>>
>>>for i in pc:
>>> i = anyclass()
>>>
>>>a.shutdown ()
>>>b.update()[/color]
>>
>>Use a dictionary:
>>
>>stuff = {}
>>pc = ['a', 'b', 'c'][/color]
>
>
> I think what he wants to do is basically hold object names in a tuple
> list, and then call the methods on those objects (while iterating or
> whatever).
>
>[color=green]
>>for i in pc:
>> stuff[i] = anyclass()
>>
>>stuff['a'].shutdown()
>>stuff['b'].update()
>>--
>>http://mail.python.org/mailman/listinfo/python-list
>>[/color]
>[/color]

Try this:

pc=["a","b","c"]
for i in pc:
vars()[i] = anyclass()
a.shutdown()
b.update()

MikeG

[Mike Gould]

Re: Variable Variable

Premshree Pillai wrote:[color=blue]
> On Sat, 19 Mar 2005 04:35:47 -0500, Leif K-Brooks <eurleif@ecritt ers.biz> wrote:
>[color=green]
>>Tanteauguri wrote:
>>[color=darkred]
>>>Hi List, is there in python a variable variable like in PHP ($$var)?
>>>
>>>What I want to do is something like that:
>>>
>>>pc=["a","b","c"]
>>>
>>>for i in pc:
>>> i = anyclass()
>>>
>>>a.shutdown ()
>>>b.update()[/color]
>>
>>Use a dictionary:
>>
>>stuff = {}
>>pc = ['a', 'b', 'c'][/color]
>
>
> I think what he wants to do is basically hold object names in a tuple
> list, and then call the methods on those objects (while iterating or
> whatever).
>
>[color=green]
>>for i in pc:
>> stuff[i] = anyclass()
>>
>>stuff['a'].shutdown()
>>stuff['b'].update()
>>--
>>http://mail.python.org/mailman/listinfo/python-list
>>[/color]
>[/color]

Try this:

pc=["a","b","c"]
for i in pc:
vars()[i] = anyclass()
a.shutdown()
b.update()

MikeG

[Mike Gould]

Re: Variable Variable

Premshree Pillai wrote:[color=blue]
> On Sat, 19 Mar 2005 04:35:47 -0500, Leif K-Brooks <eurleif@ecritt ers.biz> wrote:
>[color=green]
>>Tanteauguri wrote:
>>[color=darkred]
>>>Hi List, is there in python a variable variable like in PHP ($$var)?
>>>
>>>What I want to do is something like that:
>>>
>>>pc=["a","b","c"]
>>>
>>>for i in pc:
>>> i = anyclass()
>>>
>>>a.shutdown ()
>>>b.update()[/color]
>>
>>Use a dictionary:
>>
>>stuff = {}
>>pc = ['a', 'b', 'c'][/color]
>
>
> I think what he wants to do is basically hold object names in a tuple
> list, and then call the methods on those objects (while iterating or
> whatever).
>
>[color=green]
>>for i in pc:
>> stuff[i] = anyclass()
>>
>>stuff['a'].shutdown()
>>stuff['b'].update()
>>--
>>http://mail.python.org/mailman/listinfo/python-list
>>[/color]
>[/color]

Try this:

pc=["a","b","c"]
for i in pc:
vars()[i] = anyclass()
a.shutdown()
b.update()

MikeG