On Dec 24, 7:04 pm, "Malcolm Greene" wrote:
> Hi Roger,
>
> By very large dictionary, I mean about 25M items per dictionary. Each
> item is a simple integer whose value will never exceed 2^15.
In Python-speak about dictionaries, an "item" is a tuple (key, value).
I presume from the gross differen
Marc 'BlackJack' Rintsch wrote:
On Wed, 24 Dec 2008 03:23:00 -0500, python wrote:
collection, I don't see the advantage of using an iterator or a list.
I'm sure I'm missing a subtle point here :)
`keys()` creates a list in memory, `iterkeys()` does not. With
``set(dict.keys())`` there is a
Gabriel Genellina wrote:
En Wed, 24 Dec 2008 06:23:00 -0200, escribió:
... k1 = set(dict1.iterkeys())
You've got an excelent explanation from Marc Rintsch. (Note that in
Python 3.0 keys() behaves as iterkeys() in previous versions, so the
above code is supposed to be written in Python 2.x)
Peter Otten:
> >>> a = dict(a=1, b=2, c=3)
> >>> b = dict(b=2, c=30, d=4)
> >>> dict(set(a.iteritems()) ^ set(b.iteritems()))
For larger sets this may be better, may avoid the creation of the
second set:
dict(set(a.iteritems()).symmetric_difference(b.iteritems()))
Bye,
bearophile
--
http://mail.
08 07:10:16 -0200
Subject: Re: Strategy for determing difference between 2 very large
dictionaries
En Wed, 24 Dec 2008 06:23:00 -0200, escribió:
> Hi Gabriel,
>
> Thank you very much for your feedback!
>
>> k1 = set(dict1.iterkeys())
>
> I noticed you suggested .iterkeys
x27;: 3, 'd': 4}
That's very cool! Thanks for sharing that technique.
Regards,
Malcolm
- Original message -
From: "Peter Otten" <__pete...@web.de>
To: python-list@python.org
Date: Wed, 24 Dec 2008 09:46:51 +0100
Subject: Re: Strategy for determing differ
En Wed, 24 Dec 2008 06:23:00 -0200, escribió:
Hi Gabriel,
Thank you very much for your feedback!
k1 = set(dict1.iterkeys())
I noticed you suggested .iterkeys() vs. .keys(). Is there any advantage
to using an iterator vs. a list as the basis for creating a set? I
You've got an excelent ex
Hi James,
> For the purpose of perpetuating the annoying pedantry that has made
> usenet great:
>
> http://docs.python.org/dev/3.0/whatsnew/3.0.html#views-and-iterators-instead-of-lists
Great tip! Thank you!
Malcolm
--
http://mail.python.org/mailman/listinfo/python-list
Marc 'BlackJack' Rintsch wrote:
On Wed, 24 Dec 2008 03:23:00 -0500, python wrote:
Hi Gabriel,
Thank you very much for your feedback!
k1 = set(dict1.iterkeys())
I noticed you suggested .iterkeys() vs. .keys(). Is there any advantage
to using an iterator vs. a list as the basis for creating a
Gabriel Genellina wrote:
> En Wed, 24 Dec 2008 05:16:36 -0200, escribió:
[I didn't see the original post]
>> I'm looking for suggestions on the best ('Pythonic') way to
>> determine the difference between 2 very large dictionaries
>> containing simple key/value pairs.
>> By difference, I mean a
explanation.
Thank you!
Malcolm
- Original message -
From: "Marc 'BlackJack' Rintsch"
To: python-list@python.org
Date: 24 Dec 2008 08:30:41 GMT
Subject: Re: Strategy for determing difference between 2 very large
dictionaries
On Wed, 24 Dec 2008 03:23:00 -0
On Wed, 24 Dec 2008 03:23:00 -0500, python wrote:
> Hi Gabriel,
>
> Thank you very much for your feedback!
>
>> k1 = set(dict1.iterkeys())
>
> I noticed you suggested .iterkeys() vs. .keys(). Is there any advantage
> to using an iterator vs. a list as the basis for creating a set? I
> understan
s much better than the list comprehension approach I was
struggling with. Your dictionary comprehension statement describes
exactly what I wanted to write.
Regards,
Malcolm
- Original message -
From: "Gabriel Genellina"
To: python-list@python.org
Date: Wed, 24 Dec 2008 05:46:04 -0200
S
ime.
Thank you for sharing your thoughts with me.
Regards,
Malcolm
- Original message -
From: "Roger Binns"
To: python-list@python.org
Date: Tue, 23 Dec 2008 23:26:49 -0800
Subject: Re: Strategy for determing difference between 2 very large
dictionaries
-BEGIN PGP SIGNE
On Tue, Dec 23, 2008 at 11:46 PM, Gabriel Genellina
wrote:
>
> Yes; but isn't a dict comprehension more adequate?
>
> [key: (dict1[key], dict2[key]) for key in common_keys if
> dict1[key]!=dict2[key]}
That initial [ should be a { of course.
Cheers,
Chris
--
Follow the path of the Iguana...
En Wed, 24 Dec 2008 05:16:36 -0200, escribió:
I'm looking for suggestions on the best ('Pythonic') way to
determine the difference between 2 very large dictionaries
containing simple key/value pairs.
By difference, I mean a list of keys that are present in the
first dictionary, but not the seco
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
pyt...@bdurham.com wrote:
> Feedback on my proposed strategies (or better strategies) would be
> greatly appreciated.
Both strategies will work but I'd recommend the second approach since it
uses already tested code written by other people - the chanc
I'm looking for suggestions on the best ('Pythonic') way to
determine the difference between 2 very large dictionaries
containing simple key/value pairs.
By difference, I mean a list of keys that are present in the
first dictionary, but not the second. And vice versa. And a list
of keys in common b
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