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

==== [MESSAGE SEPARATOR] ====

```

• Prev by Date: Re: 80 bit floating point math
• Next by Date: Re: Display Region Programmable ?
• Previous by thread: Re: How do I use Select[list,condition]?
• Next by thread: Re: How do I use Select[list,condition]?