RE: Position of element in a list
- To: mathgroup at smc.vnet.net
- Subject: [mg16352] RE: [mg16301] Position of element in a list
- From: "Jean-Marie THOMAS" <jmthomas at agat.net>
- Date: Thu, 11 Mar 1999 02:16:34 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Position[{-1,0,1},_?Negative] will give you your answer.
Examine FullForm[-_] to understand the reason why!
-----Original Message-----
From: Roger Mason [mailto:rmason at sparky2.esd.mun.ca]
To: mathgroup at smc.vnet.net
Subject: [mg16352] [mg16301] Position of element in a list
Hi,
I want to find the Position[] of negative elements in a list. The obvious
methods do not work:
Position[{-1, 3, -2, 1}, -_]
and
Position[{-1, 3, -2, 1}, -x_]
return
{}
So how do I perform this apparently simple task?
Thanks,
Roger Mason