How to select the particular value and store ias a variable?

I have x values as

[2 4 6 10 8]

and coressponding y values as

 y = [0.25 0.45 0.55 0.65 0.75]

Now,i allow to generate random number. Suppose i get a number as 0.675. Then this 0.675 is going to be searched in y variable. but there is two value closer to that, that is 0.65 and 0.75. In that case it goes to check that for y=0.65 the x value is 10 and for y=0.75 x is 8. The min value of x is 8 that is taken out and stored in new variable z.

Answer 1

[dpb]

abs(0.65-0.675) = 0.025
abs(0.75-0.675) = 0.075

so it's not clear how you want 8 as the result instead of 10 as it is the nearest, clearly.

Perhaps you mean the first location for which

>> x(find(y>0.675,1,'first'))
ans =
   8
>>

maybe??

[Raja R]

in my problem, c variable size is 5X3

   1   45  0.12

   2   50  0.35

   3   75  0.65

   4   60  0.85

   5   95  0.95

Now,i allow to generate random number. Suppose i get a number as 0.675. Then this 0.675 is going to be searched in y variable. but there is two value closer to that, that is 0.65 and 0.85. In that case it goes to check that for y=0.65 the x value is 75 and for y=0.85 x is 60. The min value of x is 8 that is taken out and stored in new variable z. z=[4 60 0.85]

like so

[dpb]

That's simply repeating the same description which doesn't make sense...in what manner, specifically, is "two value closer to that, that is 0.65 and 0.85" to be interpreted so that is, indeed so?

The lookup shown earlier works as well if you simply search over the appropriate column of c and select the appropriate indices for whichever values you wish in the end result. The problem is understanding how you actually determine which is the proper row to choose as clearly it is not the closest in absolute difference.

Answer 2

[Roger Stafford]

   r = rand;
   t1 = (y>=r);
   t2 = (y<=r);
   if any(t1)
     [~,i1] = min(y(t1));
     if any(t2)
       [~,i2] = max(y(t2));
       z = min(x(i1),x(i2));
     else
       z = x(i1);
     end
   else  % If t1 was empty, then t2 will not be
     [~,i2] = max(y(t2));
     z = x(i2);
   end