I have a matrix and I am trying to find where i getting a value. so, i am using `find(x==y)`for making vectors with the values, for example:

```
n11=find(x==11)
n4=find(x==4)
n8=find(x==8)

```

And n11, n4, n8 are not of the same length. 

Sometimes, i have to do this like 20 or 30 times for 20 or 30 different values of x, so if for example i want to get an interval of x∈[1991,2015] `find(x==1991) to find(x==2015)` how can i get those values faster without doing

```
find(x==1991)
.
.
.
find(x==2015)

```

thank you