[Solved] How to count occurrence of a value across multiple data frames [duplicate]

by


We can use rbindlist

library(data.table)
rbindlist(mget(paste0("df", 1:3)))[, .N, Id]\
#   Id N
#1:  1 2
#2:  2 3
#3:  3 1
#4:  4 2
#5:  7 1
#6:  6 1
#7:  9 1
#8: 11 1

solved How to count occurrence of a value across multiple data frames [duplicate]