Can I control filter command?

Assuming I have a function an equation like

y[n]=x[n]-y[n-1] with the condition that y[n]=0 if n<0

can I implement and solve this using filter command? or should I solve it in another way?

Answer 1

[per isakson]

Yes, filter() is possible. Try

y = filter( 1, [1,1], x );

[Mohamed Salah]

I was trying the same line of code but with vaiables a,b and it didn't produce the correct values, but somehow the line did solve the problem. Thanks!