Dear all, Please apologyse if this is too simple. I am a beginner. I am trying to extract the resulting output of each iteration in a for() loop in order to concatenate them and make an histogram out of that. Example: a<-c(1,2,3,3,3,4,6,7,7,8) b<-c(5,8) # function to obtain 2 (length of "a") vectors, each corresponding to b<=a (b<=5 and b<=8) fun<-function(x,y){ ???? for(y in y){ ???? ??? cat(y,":",x[x<=y],"\n") ???? ??? } ???? ?} fun(a,b) #result Question: I want to concatenate the resulting vectors (the "5" and the "9") to make an histogram. I could just copy and paste them, but I want to do this with thousands of vectors (each one resulting from an iteration, which can be a vector of potential enormous length). I would really appreciate some help. Thanks, Duarte Viana