r - 在 r 中加入多个数据框

Question

a1 <- data.frame(id=c(1,1,1,1,2,2,2,3,3),
                var=c("6402","1","1","3","6406","6406","2","1","1"))
b1 <- data.frame(var=c("6402","6406"),
                txt=c("A","B"))
n1 <- data.frame(id=c(1,2,3))


desired <- data.frame(id=c(1,2,3),
                      txt=c("A","B",NA))

如何连接 a1、b1 和 n1 以生成所需的 df？

Answer 1

我们可以使用tidyverse

library(dplyr)
distinct(a1) %>%
   left_join(b1, by = 'var') %>% 
   full_join(n1) %>%
   group_by(id) %>%
   summarise(txt = first(txt))
# A tibble: 3 x 2
#     id txt  
#  <dbl> <chr>
#1     1 A    
#2     2 B    
#3     3 <NA> 

---

或者使用data.table

unique(setDT(a1))[b1,  txt := txt, on = .(var)][n1, .SD[1],
      on = .(id), by = .EACHI][, var := NULL][]