Counting number of individuals between a box

Hello,

I have 7000 particles scattered in an area. I would like to count the number of them in one particular area delimited by fixed coordinates. For example:

Particles number Coordinates X Coordinates Y

1 25 58

2 18 30

3 5 45

4 26 60

5 27 61

6 14 70

How many particles are located in the area: 20<x<30 and 57<y<71? The aswer should be: 3

Thank you for your help.

Jonathan

Answer 1

[Star Strider]

Try this:

A = [1    25    58
     2    18    30
     3     5    45
     4    26    60
     5    27    61
     6    14    70];

Count = nnz(A(:,2)>20 & A(:,2)<30 & A(:,3)>57 & A(:,3)<71)

producing:

Count =
     3

.