How to interpolate a value between two values in an array?

Hi,i have an array named sumNy. the content of sumNy gives me Ny and the number of it's cells show me corresponding accelerations. now i have a specified Ny that is between two Ny s in my sumNy array, and i want to obtain it's corresponding acceleration.

i wrote this code but i dont know why it is not working

 for i=1:150
  if i==1
   y=0;
   elseif sumNy1(1,i-1)<=(1/475) & sumNy1(1,i)>=(1/475)
   y=(((1/475)-sumNy1(1,i))/(sumNy1(1,i-1)-sumNy1(1,i)))*(i-1)+(1-(((1/475)- sumNy1(1,i))/(sumNy1(1,i-1)-sumNy1(1,i))))*(i);
  end
 end

please help me

Thanks

[Arman Kam]

i must say that (1/475) is my specified Ny

[Arman Kam]

and by the way, there is two Ny s in my array that the specified Ny (1/475) place between them, so that is not why everytime i run this code it gives me y=0 !

Answer 1

[Wayne King]

Have you tried interp1?

For example:

   t = 0:10; x = sin(t); 
   tnew = 0:.25:10;
   xnew = interp1(t,x,tnew); 
   plot(t,x,'o',tnew,xnew)

[Arman Kam]

i dont know what to put as a function in interp1 that gives me linear interpolation.

[Arman Kam]

i think the code i wrote do what i want but everytime i try this code the value of y will be zero!

would you please help me whats wrong with this code?!

Answer 2

[Arman Kam]

sorry friends, i just find out my horrible mistake!

but still if you have a better way to do this please tell me