python sorting 2dim. array ?

[fredo66@fulladsl.be]

hello,
Can someone help me with this:
I have a array like this

list[rowindex][colomindex]

where rows are the records and colom the fields. If I use the .sort()
method on 'list' the data is sorted on the items of the first colom.
But I want to sort on the second colom as first (and as second
sortfield the first colom).

What is the shortest code for this pls ?

(all fields are text value, first colom is name, second category)

[fredo66@fulladsl.be]

Re: python sorting 2dim. array ?

remark: The server is using python server version 2.3.4

[Peter Otten]

Re: python sorting 2dim. array ?

fredo66@fullads l.be wrote:

hello,
Can someone help me with this:
I have a array like this
>
list[rowindex][colomindex]
>
where rows are the records and colom the fields. If I use the .sort()
method on 'list' the data is sorted on the items of the first colom.
But I want to sort on the second colom as first (and as second
sortfield the first colom).
>
What is the shortest code for this pls ?
>
(all fields are text value, first colom is name, second category)

>>items = [(1,2), (2,2), (2,1)]
>>items.sort(la mbda x, y: cmp(x[1::-1], y[1::-1]))
>>items

[(2, 1), (1, 2), (2, 2)]

If you want something more efficient, see

http://www.python.org/doc/faq/programming/#i-want-to-do-a-complicated-sort-can-you-do-a-schwartzian-transform-in-python

Peter

[bearophileHUGS@lycos.com]

Re: python sorting 2dim. array ?

fred...@fullads l.be:

list[rowindex][colomindex]
I want to sort on the second colom as first (and as
second sortfield the first colom).

A good way, in Python 2.5:

>>from operator import itemgetter
>>a = [[1, 2], [3, 1], [2, 5], [7, 1]]
>>a.sort(key=it emgetter(1, 0))
>>a

[[3, 1], [7, 1], [1, 2], [2, 5]]

Bye,
bearophile