I am working on a dictionary sorting problem just like the one in the email
thread at the bottom of this message. My question about their solution is:
In these lines:
lst.sort(lambda m, n: cmp(m.get(field), n.get(field)))
where field is either 'name' or 'size'.
What is "n:" and what is "lambda m" ?
Thank You,
John A. Gooch
-----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'.
As a function:
def sort_it (lst, field):
lst.sort(lambda m, n: cmp(m.get(field), n.get(field)))
Karl
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