# Moving Between States in a Markov Model - How to Tell R?

I have been struggling with this problem for quite a while and any help would be much appreciated.

I am trying to write a function to calculate a transition matrix from observed data for a markov model.

My initial data I am using to build the function look something like this;

Season Team State 1 1 Manchester United 1 2 1 Chelsea 1 3 1 Manchester City 1 . . . 99 5 Charlton Athletic 4 100 5 Watford 4

with 5 seasons and 4 states.

I know how I am going to calculate the transition matrix, but in order to do this I need to count the number of teams that move from state i to state j for each season.

I need code that will do something like this,

a<-function(x,i,j){ if("team x is in state i in season 1 and state j in season 2") 1 else 0 } sum(a)

and then I could do this for each team and pair of states and repeat for all 5 seasons. However, I am having a hard time getting my head around how to tell R the thing in quotation marks. Sorry if there is a really obvious answer but I am a rubbish programmer.

Thanks so much for reading!