Thread Subject: Setting specific values to zero or nan?

Hello,
I am stuck..I have 3 large matrices x,y,z. I'm trying to
set all the values less than 5 to zero(zeros) or NAN and
the corresponding cells in the y and z matrix.

Is this possible? I have used the below which is not
working.

a=find (x<5)
x = ZEROS(:,o)

Thanks

"Ali Hussain" <hussaizj@aston.ac.uk> wrote in message
<g3qif2$3m1$1@fred.mathworks.com>...
> Hello,
> I am stuck..I have 3 large matrices x,y,z. I'm trying to
> set all the values less than 5 to zero(zeros) or NAN and
> the corresponding cells in the y and z matrix.
>
> Is this possible? I have used the below which is not
> working.
>
> a=find (x<5)
> x = ZEROS(:,o)
>
> Thanks

LHF for the taking.

One of thousands of answers:

x(x<5)=0;

"Ali Hussain" <hussaizj@aston.ac.uk> writes:

>Hello,
>I am stuck..I have 3 large matrices x,y,z. I'm trying to
>set all the values less than 5 to zero(zeros) or NAN and
>the corresponding cells in the y and z matrix.

>a=find (x<5)
Then do
  x(a)=0;
  y(a)=0;
  z(a)=0;

tpl@eng.cam.ac.uk (Tim Love) wrote in message
<g3qj4u$3ug$1@gemini.csx.cam.ac.uk>...
> "Ali Hussain" <hussaizj@aston.ac.uk> writes:
>
> >Hello,
> >I am stuck..I have 3 large matrices x,y,z. I'm trying to
> >set all the values less than 5 to zero(zeros) or NAN and
> >the corresponding cells in the y and z matrix.
>
> >a=find (x<5)
> Then do
> x(a)=0;
> y(a)=0;
> z(a)=0;


I have done that with my matrix. When I use the surface
plot it plots the zero values too. What i basically want to
do is to get rid of those numbers so it doesnt show in the
plot at all. So I have tried to use NAN but how would I
set that for the same range of values as above

"Ali Hussain" <hussaizj@aston.ac.uk> wrote in message
<g3qjtt$f4v$1@fred.mathworks.com>...
> tpl@eng.cam.ac.uk (Tim Love) wrote in message
> <g3qj4u$3ug$1@gemini.csx.cam.ac.uk>...
> > "Ali Hussain" <hussaizj@aston.ac.uk> writes:
> >
> > >Hello,
> > >I am stuck..I have 3 large matrices x,y,z. I'm trying to
> > >set all the values less than 5 to zero(zeros) or NAN and
> > >the corresponding cells in the y and z matrix.
> >
> > >a=find (x<5)
> > Then do
> > x(a)=0;
> > y(a)=0;
> > z(a)=0;
>
>
> I have done that with my matrix. When I use the surface
> plot it plots the zero values too. What i basically want to
> do is to get rid of those numbers so it doesnt show in the
> plot at all. So I have tried to use NAN but how would I
> set that for the same range of values as above


No need to use find, use logical indexing. Secondly, you can
set these elements to whatever value you want, including NaNs

An example:

x = [6 2 7 8 3 9]
y = [2 8 4 8 9 2]

a = x < 5 ;
x(a) = 0
y(a) = NaN

hth
Jos