Re: How do I use Select[list,condition]?
- To: mathgroup at smc.vnet.net
- Subject: [mg4546] Re: How do I use Select[list,condition]?
- From: Nate Brixius <brixius at cs.uiowa.edu>
- Date: Wed, 7 Aug 1996 04:17:52 -0400
- Organization: The University of Iowa
- Sender: owner-wri-mathgroup at wolfram.com
Jason Welter wrote:
>
> I have a list that looks like:
>
> data = {{1,1,a,4,5,6},{2,1,a,2,3,4},{3,1,a,7,8,9},
> {1,2,b,4,5,6},{2,2,b,2,3,4},{3,2,b,7,8,9},
> {1,3,c,4,5,6},{2,3,c,2,3,4},{3,3,c,7,8,9}}
>
> and I want to pick out the lists that have a 2 as the second element
> of the list. I tried something like:
>
> data1 = Select[data,data[[#,2]]==2];
>
> but this doesn't work. How do I do it?
Try the following:
data = {{1,1,a,4,5,6},{2,1,a,2,3,4},{3,1,a,7,8,9},
{1,2,b,4,5,6},{2,2,b,2,3,4},{3,2,b,7,8,9},
{1,3,c,4,5,6},{2,3,c,2,3,4},{3,3,c,7,8,9}}
data1 = Select[data,(#[[2]]==2)&]
Output:
Out[58]=
{{1, 1, a, 4, 5, 6}, {2, 1, a, 2, 3, 4}, {3, 1, a, 7, 8, 9},
{1, 2, b, 4, 5, 6}, {2, 2, b, 2, 3, 4}, {3, 2, b, 7, 8, 9},
{1, 3, c, 4, 5, 6}, {2, 3, c, 2, 3, 4}, {3, 3, c, 7, 8, 9}}
Out[59]=
{{1, 2, b, 4, 5, 6}, {2, 2, b, 2, 3, 4}, {3, 2, b, 7, 8, 9}}
I hope this helps.
Nate
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