How do I sum the values of columns in several tables if tables have different lengths?

Question

Alright, this should be an easy one but I\'m looking for a solution that\'s as fast as possible.

Let\'s say I have 3 tables (the number of tables will be much larger

Answer 1

We concatenate (c) the tab output to create 'v1', use tapply to get the sum of the elements grouped by the names of that object.

v1 <- c(tab1, tab2, tab3)
tapply(v1, names(v1), FUN=sum)
#1 2 3 4 5 
#7 3 4 3 1