Re: List Question
- To: mathgroup at smc.vnet.net
- Subject: [mg67918] Re: List Question
- From: albert <awnl at arcor.de>
- Date: Thu, 13 Jul 2006 06:53:04 -0400 (EDT)
- References: <e92e03$ljm$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Simon Bale wrote:
> Hi,
>
> I have a list with the following structure:
>
> {{x1,y1},{x2,y2},{x3,y3,z3},{x4,y4}...}
>
> As you can see some of the data points have three elements. I would
> like to remove these z elements so that the list has a structure
> {{x1,y1},{x2,y2},{x3,y3},{x4,y4}...}. I'm not sure how to achieve this
> so any
> help is greatly appreciated.
lst = {{x1, y1}, {x2, y2}, {x3, y3, z3}, {x4, y4}};
Replace[lst, {a_, b_, c__} -> {a, b}, {1}]
Using Replace with a third argument gives you good control of where the
replacement is tried. Using c__ instead just c__ will make the Replace work
even if there are data points with more than three elements...
hth,
albert