R help - Dec 2007 - how to threshold a matrix

Dear list,

I have a matrix M (2500 rows and 9 columns). It looks like

2.2     0.1      2.6    3.6 ......
0.4     1.9      2.7    4.2......
1.8     2.5      4.3    2.2.......
.....................

If I want to do:

(1) if M[i,j]>=0.3, M[i,j]=1
(2) if M[i,j]<=-0.3, M[i,j]=-1
(3) Otherwise, M[i,j]=0

Is there a way to ceil and floor the data?

Thanks a lot!

Allen

	[[alternative HTML version deleted]]

Try:

(M >= 0.3) - (M <= 0.3)

On Dec 15, 2007 10:56 AM, affy snp <affysnp at gmail.com>
wrote:
> Dear list,
>
> I have a matrix M (2500 rows and 9 columns). It looks like
>
> 2.2     0.1      2.6    3.6 ......
> 0.4     1.9      2.7    4.2......
> 1.8     2.5      4.3    2.2.......
> .....................
>
> If I want to do:
>
> (1) if M[i,j]>=0.3, M[i,j]=1
> (2) if M[i,j]<=-0.3, M[i,j]=-1
> (3) Otherwise, M[i,j]=0
>
> Is there a way to ceil and floor the data?
>
> Thanks a lot!
>
> Allen
>
>        [[alternative HTML version deleted]]
>
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