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From: Gabriel Genellina on 5 Jun 2010 06:11
On 31 mayo, 08:11, moerchendiser2k3 <googler.
1.webmas...(a)spamgourmet.com> wrote:

> you are right, Python still holds the last
> reference. I just set a dummy and thats it :)
>
> Can you tell me where did you get the information from?

Do you mean the _ variable?
It's in the tutorial:
http://docs.python.org/tutorial/introduction.html#using-python-as-a-calculator

--
Gabriel Genellina
From: moerchendiser2k3 on 6 Jun 2010 06:30
thx, thats it! :)
From: Mark Lawrence on 17 Jun 2010 17:32
On 05/06/2010 11:11, Gabriel Genellina wrote:
> On 31 mayo, 08:11, moerchendiser2k3<googler.
> 1.webmas...(a)spamgourmet.com> wrote:
>
>> you are right, Python still holds the last
>> reference. I just set a dummy and thats it :)
>>
>> Can you tell me where did you get the information from?
>
> Do you mean the _ variable?
> It's in the tutorial:
> http://docs.python.org/tutorial/introduction.html#using-python-as-a-calculator
>
> --
> Gabriel Genellina

I have always believed that the _ variable is only available
interactively because of this comment in the tutorial:-
"In interactive mode, the last printed expression is assigned to the
variable _. This means that when you are using Python as a desk
calculator, it is somewhat easier to continue calculations, for example:
...."

However a thread from IIRC a couple of days back used _ to say "I'm not
interested in you, I'm throwing you away" in a list comprehension or
whatever. I've tried this in a script this evening and it works perfectly.

print 'total', sum(amount for _, amount in outputs)

Where is the use of _ in a script documented, I've searched all over and
can't find it, guess I don't have the Midas touch with google? :)

Kindest regards.

Mark Lawrence.

From: Stephen Hansen on 17 Jun 2010 17:51
On 6/17/10 2:32 PM, Mark Lawrence wrote:
> Where is the use of _ in a script documented, I've searched all over and
> can't find it, guess I don't have the Midas touch with google? :)

Its purely a convention, and one that crosses language-bounds, and isn't
entirely universal even given that.

It just means 'placeholder that I care naught for'; its not a feature,
there's no code or any /ability/ to use it. Its the same as any other
variable name.

It just happens to be a name that conveys no meaning while being short
and visually distinct: except to say you don't care about what value
ends up there, consider it thrown away.

That the interactive interpreter happens to store the last value in a
variable of the same name doesn't really mean anything.

--

Stephen Hansen
... Also: Ixokai
... Mail: me+list/python (AT) ixokai (DOT) io
... Blog: http://meh.ixokai.io/

From: Mark Lawrence on 17 Jun 2010 19:18
On 17/06/2010 22:51, Stephen Hansen wrote:
> On 6/17/10 2:32 PM, Mark Lawrence wrote:
>> Where is the use of _ in a script documented, I've searched all over and
>> can't find it, guess I don't have the Midas touch with google? :)
>
> Its purely a convention, and one that crosses language-bounds, and isn't
> entirely universal even given that.
>
> It just means 'placeholder that I care naught for'; its not a feature,
> there's no code or any /ability/ to use it. Its the same as any other
> variable name.
>
> It just happens to be a name that conveys no meaning while being short
> and visually distinct: except to say you don't care about what value
> ends up there, consider it thrown away.
>
> That the interactive interpreter happens to store the last value in a
> variable of the same name doesn't really mean anything.
>
>

Thanks Stephen, don't think I'll lose any sleep over it then. :)

Cheers.

Mark Lawrence.

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