Gooch, John wrote:
Ken,
I misspoke when I said these were lists of dictionaries, they are actually
lists of object that have a "getSize()" getter function that returns the
size of their contents, which I would like to use for sorting.
It the objects are instances of SomeClass, I think you could use
lst.sort(key=SomeClass.getSize)
otherwise you could use
lst.sort(key=lambda x: x.getSize())
Kent
Thank You,
John A. Gooch
Systems Administrator
IT - Tools
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-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Kent Johnson
Sent: Wednesday, April 13, 2005 3:52 AM
Cc: tutor@python.org
Subject: Re: [Tutor] sorting a list of dictionaries
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Thursday, December 09, 2004 12:19 PM
To: tutor@python.org
Subject: Re: [Tutor] sorting a list of dictionaries
On 9 Dez 2004, [EMAIL PROTECTED] wrote:
I have a list of dictionaries, each representing info about a file,
something like:
[{'name':'foo.txt','size':35}, {'name':'bar.txt','size':35}, ...]
I want to present a sorted list of all the files' data, sorting on the
keys 'name' or 'size'. The file 'name' s should be unique (I'm hoping)
across all the dictionaries. Can someone point me towards an efficient
solution for accomplishing the sort? (The list has 1000s of files).
That's easy to achieve, since sort takes a custom sort function as
optional argument. Now you need only a function which takes the
values of the fileds and compares them.
E.g.
lst.sort(lambda m, n: cmp(m.get(field), n.get(field)))
where field is either 'name' or 'size'.
In Python 2.4 a more efficient way of doing this is to use the key parameter
to sort() with an
itemgetter function:
from operator import itemgetter
lst.sort(key=itemgetter('field'))
Kent
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