Hi, I have written a function, ( or 2 functions) becasue there are only tiny difference, One of them has lines =========================#c2 (price.mat) call option price c2=c( max(S.mat[1,3]-K,0), max(S.mat[2,3]-K,0), max(S.mat[3,3]-K,0) ) (some lines) list( "Stock Value"=round(S.mat,dp), "Call Price"=round(price.mat,dp), "Phi"=round(phi.mat,dp), "Psi"=round(psi.mat,dp) ) ========================== and the other one is =========================#c2 (price.mat) put option price c2=c( max(K-S.mat[1,3],0), <---------difference max(K-S.mat[2,3],0), <---------difference max(K-S.mat[3,3],0) <---------difference ) (some lines) list( "Stock Value"=round(S.mat,dp), "Put Price"=round(price.mat,dp), <---------"label" difference "Phi"=round(phi.mat,dp), "Psi"=round(psi.mat,dp) ) ========================== Can I combine them into one function? just by adding a 'dummy variable' say 'type' which takes "call"/"put" or values 1,2 The full codes are in attachment. Thanks! http://n4.nabble.com/file/n1835638/mycall.r mycall.r http://n4.nabble.com/file/n1835638/myput.r myput.r casper -- View this message in context: http://n4.nabble.com/writing-function-help-tp1835638p1835638.html Sent from the R help mailing list archive at Nabble.com.