Re: Problems ....
- To: mathgroup@smc.vnet.net
- Subject: [mg11585] Re: Problems ....
- From: Allan Hayes <hay@haystack.demon.co.uk>
- Date: Tue, 17 Mar 1998 10:43:06 -0500
- References: <6ecfs2$5ba@smc.vnet.net>
Tie wrote:
> Anyone can
> help me do the following:
>
> 1. Let Y={a,b} and let X be an arbitrary numeric vector. Replace all
> occurances of a in X with b.
>
> 2. Sort the elements of X in ascending order of absolute value.
>
> 3. Square each elements of a vector X but keep its sign.
>
> 4. Remove second element of the vector X without using the Table
> function
Tie:
Y= {2,-1};
X = {-3,2,5,2}
{-3,2,5,2}
1)
X/.Rule@@Y (*Rule@@Y gives 2->-1*)
{-3,-1,5,-1}
2)
Sort[X, Abs[#]<=Abs[#2]&]
{2,2,-3,5}
3)
X X Sign[X]
{-9,4,25,4}
4)
Drop[X,{2}]
{-3,5,2}
--
Allan Hayes
Training and Consulting
Leicester, UK
hay@haystack.demon.co.uk
http://www.haystack.demon.co.uk
voice: +44 (0)116 271 4198
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