Given list test, how do I find any numbers that repeat exactly 3 times in test[[2]] and 4 times in test[[3]]? In this particular example, I want an output that gives me 3 and 6 in [[2]] and 10 in [[3]].
test <- list(c(1:10),c(1:10,3,3,6,6),c(1:10,10,10,10))
I am able to generate a table for each vector, test2.
lapply(test,table)
But when I tried to equate the table to 1:3, which I stored as the names of test, I get logical(0) for each vector.
names(test) <- 1:3
lapply(test,function(x) table(x)==names(x))
Any idea what went wrong and what the simplest solution is?
If you run lapply(test, names) you would see that the names function applied to each list element just returns NULL. Under the hood I think lapply is just passing the contents of the sublist and not the sublist itself to the function (just like when you use double square brackets to subset - try comparing names(test[[1]]) to names(test[1])).
Using your original idea, if what you want is a vector of logicals, you could try this instead:
lapply(1:3, function(x) table(test[x]) == x)