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| From | harrismh777 <harrismh777@charter.net> |
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| Subject | Re: Something is rotten in Denmark... |
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| Date | Tue, 31 May 2011 15:18:37 -0500 |
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Terry Reedy wrote:
> You have been hypnotizeed by lambda. (lambda n: i+n) is a *constant
> expression*, so you get 10 'equal' functions.
'hypnotized' indeed! ... ok, so let me see if I get this... the lambda
defers lookup|bind of its references until such time as the lambda is
'called' and not at the time (as I thought) that the anonymous
function(s) are returned?
If I'm understanding that correctly, then that means lambda is working
as designed, and that there are very subtle nuances to be aware of. In
my little case
(lambda n: i + n)
... if the i goes out of scope before the anonymous function gets
called then we have a problem... or if i as a reference is mutable or
refers to a different object before the anonymous function is called
then we have a problem?
What I am discovering is that 'yes' I can use lambda syntactically
where I might not be able to code a def statement; however, if I do use
it (as in a list comprehension) then I may get unexpected results if any
of my lambda's references go out of scope or are mutable...(?)
Question:
What are the ramifications of making the lookup|binding happen at
the time the anonymous function is 'returned' vs 'called'? Has anyone
suggested this? Is this PEP-able....? Are there side-effects in the
other direction?
PS Thanks Chris, Ian, Jussi, Thomas, Terry... I appreciate your
teaching and patience !
kind regards,
m harris
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Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-05-31 01:48 -0500
Re: Something is rotten in Denmark... Chris Rebert <clp2@rebertia.com> - 2011-05-31 00:00 -0700
Re: Something is rotten in Denmark... Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-31 01:35 -0600
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-05-31 13:08 +0300
Re: Something is rotten in Denmark... Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-05-31 12:48 +0200
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-05-31 15:15 +0300
Re: Something is rotten in Denmark... Terry Reedy <tjreedy@udel.edu> - 2011-05-31 13:11 -0400
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-05-31 15:18 -0500
Re: Something is rotten in Denmark... Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-31 16:24 -0600
Re: Something is rotten in Denmark... Terry Reedy <tjreedy@udel.edu> - 2011-05-31 19:14 -0400
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-05-31 19:09 -0500
Re: Something is rotten in Denmark... Terry Reedy <tjreedy@udel.edu> - 2011-06-01 13:11 -0400
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-01 19:40 -0500
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-01 19:50 -0500
Re: Something is rotten in Denmark... Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-02 04:37 +0000
Re: Something is rotten in Denmark... Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-02 05:14 +0000
Re: Something is rotten in Denmark... Chris Angelico <rosuav@gmail.com> - 2011-06-02 18:02 +1000
Re: Something is rotten in Denmark... Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2011-06-02 13:00 +0200
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-06-02 15:51 +0300
Re: Something is rotten in Denmark... Terry Reedy <tjreedy@udel.edu> - 2011-06-02 15:43 -0400
Re: Something is rotten in Denmark... Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-06-03 11:43 +1200
Re: Something is rotten in Denmark... rusi <rustompmody@gmail.com> - 2011-06-02 19:24 -0700
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-06-03 09:17 +0300
Re: Something is rotten in Denmark... rusi <rustompmody@gmail.com> - 2011-06-05 03:54 -0700
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-06-05 15:03 +0300
Re: Something is rotten in Denmark... rusi <rustompmody@gmail.com> - 2011-06-05 05:26 -0700
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-06-05 16:10 +0300
Re: Something is rotten in Denmark... Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-06-03 10:30 +0200
Re: Something is rotten in Denmark... Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-03 11:53 -0600
Re: Something is rotten in Denmark... Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2011-06-03 12:35 +0200
Re: Something is rotten in Denmark... Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-06-03 14:07 +0300
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-03 15:38 -0500
Re: Something is rotten in Denmark... Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-06-04 12:40 +1200
Re: Something is rotten in Denmark... Nobody <nobody@nowhere.com> - 2011-06-03 14:07 +0100
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-02 10:44 -0500
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-02 10:55 -0500
Re: Something is rotten in Denmark... Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-02 17:22 +0000
Re: Something is rotten in Denmark... Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-02 11:43 -0600
Re: Something is rotten in Denmark... Terry Reedy <tjreedy@udel.edu> - 2011-06-02 02:02 -0400
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-06-02 11:02 -0500
Re: Something is rotten in Denmark... Martin Manns <mmanns@gmx.net> - 2011-05-31 23:14 +0200
Re: Something is rotten in Denmark... Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-31 15:47 -0600
Re: Something is rotten in Denmark... Martin Manns <mmanns@gmx.net> - 2011-06-01 02:57 +0200
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-05-31 16:53 -0500
Re: Something is rotten in Denmark... harrismh777 <harrismh777@charter.net> - 2011-05-31 17:06 -0500
Re: Something is rotten in Denmark... Chris Angelico <rosuav@gmail.com> - 2011-06-01 08:39 +1000
Re: Something is rotten in Denmark... Chris Angelico <rosuav@gmail.com> - 2011-06-01 08:40 +1000
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