Re: extracting a list to a list, help please

• To: mathgroup at smc.vnet.net
• Subject: [mg46173] Re: extracting a list to a list, help please
• From: bobhanlon at aol.com (Bob Hanlon)
• Date: Tue, 10 Feb 2004 00:05:40 -0500 (EST)
• References: <c07p1q\$kk7\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

mylist1 = {{a1,b1,c1,d1},{a2,b2,c2,d2},{a3,b3,c3,d3}};

mylist2 = mylist1[[All, {1,2}]]

{{a1, b1}, {a2, b2}, {a3, b3}}

mylist2 == (Take[#, 2]& /@ mylist1)

True

mylist2 == (Drop[#, -2]& /@ mylist1)

True

Bob Hanlon

In article <c07p1q\$kk7\$1 at smc.vnet.net>, Serge <nospam at nospam.com> wrote:

<< I made some calculations that I need for an orbit and I have a list that
look like this:

mylist1 = {{a1,b1,c1,d1},{a2,b2,c2,d2},{a3,b3,c3,d3},etc}

All I want to do is to make a list of the form

mylist2 = {{a1,b1},{a2,b2},{a3,b3},etc}

from the original list (mylist1),

so that I can ListPlot those pairs of points (they represent x and y
coordinates for some orbit). I am having trouble figuring out how to do
this. I tried using the Table command but I couldn't get it into the
above form.

• Prev by Date: Re: extracting a list to a list, help please
• Next by Date: FindRoot in Version 5
• Previous by thread: Re: extracting a list to a list, help please
• Next by thread: Re: extracting a list to a list, help please