The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Inactive » comp.soft-sys.math.mathematica

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: How do I use Select[list,condition]?
Replies: 7   Last Post: Aug 2, 1996 2:04 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Stephen P Luttrell

Posts: 121
Registered: 12/7/04
Re: How do I use Select[list,condition]?
Posted: Jul 30, 1996 2:57 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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},
Select[data, MatchQ[#, {_,2,___}]&]

which produces the output

{{1, 2, b, 4, 5, 6}, {2, 2, b, 2, 3, 4}, {3, 2, b, 7, 8, 9}}

Dr Stephen P Luttrell
Adaptive Systems Theory 01684-894046 (phone)
Room EX21, Defence Research Agency 01684-894384 (fax)
Malvern, Worcs, WR14 3PS, U.K.

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.