Re: Sort a List, in a List of Lists of Lists

• To: mathgroup at smc.vnet.net
• Subject: [mg113813] Re: Sort a List, in a List of Lists of Lists
• Date: Sun, 14 Nov 2010 06:08:27 -0500 (EST)
• References: <ibl9g2\$b8a\$1@smc.vnet.net>

```On 11/13/2010 12:59 AM, leigh.pascoe at inserm.fr wrote:
> Dear Mathgroup,
>
> I have a lsit of Lists of Lists:
>
> {{{1,2},{2,1},{1,1}},{{1,1},{1,1},{1,2}},{{2,1},{2,2},{1,2}},{{2,2},{1,2},{2,2}},{{1,1},{2,1},{1,2}},{{1,2},{2,2},{2,2}}}
>
> I would like to sort the elements in the lowest level of brackets to give
>
> {{{1, 2}, {1, 2}, {1, 1}}, {{1, 1}, {1, 1}, {1, 2}}, {{1, 2}, {2,
>      2}, {1, 2}}, {{2, 2}, {1, 2}, {2, 2}}, {{1, 1}, {1, 2}, {1,
>      2}}, {{1, 2}, {2, 2}, {2, 2}}}
>
> i.e retaining the same structure with the paired elements in the
> original order. I can't seem to get the syntax right to do this apart
> from the obvious
>
> {{Sort[{1, 2}], Sort[{2, 1}], Sort[{1, 1}]}, {Sort[{1, 1}],
>     Sort[{1, 1}], Sort[{1, 2}]}, {Sort[{2, 1}], Sort[{2, 2}],
>     Sort[{1, 2}]}, {Sort[{2, 2}], Sort[{1, 2}],
>     Sort[{2, 2}]}, {Sort[{1, 1}], Sort[{2, 1}],
>     Sort[{1, 2}]}, {Sort[{1, 2}], Sort[{2, 2}], Sort[{2, 2}]}}
>
> I must have a blind spot for the correct command. Can someone please
> help me with what should be a straightforward sort. As I want to carry
> this out on several hundred thousand pairs I need a more efficient

Look up Map in the Documentation.

list = {{{1, 2}, {2, 1}, {1, 1}}, {{1, 1}, {1, 1}, {1, 2}}, {{2,
1}, {2, 2}, {1, 2}}, {{2, 2}, {1, 2}, {2, 2}}, {{1, 1}, {2,
1}, {1, 2}}, {{1, 2}, {2, 2}, {2, 2}}}

Map[Sort, list, {2}]

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