How to compare data in one column and count the same

[diavolique]

I have a simple trouble. I need to compare data in column in my .dat file and count the number of identical data

[Momothegreat]

Man that is not really helpful. Try to post the code so we can see where you are at and what you're struggling with. Most likely you need to incorporate a check for equivalency inside a loop and setup a counter such as if(a == b) then count it.