Re: Problems ....
- To: mathgroup@smc.vnet.net
- Subject: [mg11555] Re: [mg11532] Problems ....
- From: Des Penny <penny@suu.edu>
- Date: Sat, 14 Mar 1998 13:56:09 -0500
- Organization: Southern Utah University
- References: <199803131722.MAA03809@smc.vnet.net.>
Hi:
The answers to your questions are as follows:
Tie wrote:
> I am a new user. need help to know more about mathematica. 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.
In:
x={1,3,-5,3,-4};
y={3,8};
x=x /. y[[1]]->y[[2]]
Out:
{1,8,-5,8,-4}
> 2. Sort the elements of X in ascending order of absolute value.
In:x={1,3,-5,3,-4};
x=Sort[x,Abs[#1]<Abs[#2]&]
Out:
{1,3,3,-4,-5}
>
>
> 3. Square each elements of a vector X but keep its sign.
In:x={1,3,-5,3,-4};
x=Map[Sign[#] #^2 &,x]
Out:
{1,9,-25,9,-16}
>
>
> 4. Remove second element of the vector X without using the Table
> function
>
In:x={1,3,-5,3,-4};
x=Drop[x,{2}]
Out:
{1,-5,3,-4}
> thanks.
Cheers,
--
Des Penny
Physical Science Dept.
Southern Utah University
Cedar City, UT 84720
Office: (435) 586-7708
FAX: (435) 865-8051
email: penny@suu.edu
Home: (435) 586-2286
email: dpenny@iname.com
- References:
- Problems ....
- From: tie@cscn.com (Tie)
- Problems ....