英文:
Combining two data.frames in R with left-join
问题
I have the following data.frame called "A":
structure(list(ID = c(111L, 222L, 333L, 444L, 555L, 666L)), row.names = c(NA, 6L), class = "data.frame")
along with the following data.frame called "B":
structure(list(ID = c(111L, 222L, 444L, 555L, 777L, 888L), Created.At = c("2018-10-31 06:25:20", "2019-01-19 15:42:19", "2019-01-19 15:42:50", "2020-06-30 22:04:54", "2019-01-19 15:51:48", "2019-01-19 15:51:48")), row.names = c(NA, 6L), class = "data.frame")
I need to have the following output while combining data.frame A & B and then sorting by the ID having a left-join on data.frame A:
英文:
I have the following data.frame called "A":
structure(list(ID = c(111L, 222L, 333L,444L, 555L, 666L)), row.names = c(NA, 6L), class = "data.frame")
along with the following data.frame called "B":
structure(list(ID = c(111L, 222L, 444L,555L, 777L, 888L), Created.At = c("2018-10-31 06:25:20","2019-01-19 15:42:19", "2019-01-19 15:42:50", "2020-06-30 22:04:54","2019-01-19 15:51:48", "2019-01-19 15:51:48")), row.names = c(NA,6L), class = "data.frame")
I need to have the follwing output while combining data.frame A & B and then sorting by the ID having a left-join on data.frame A:
答案1
得分: 2
library(dplyr)C <- left_join(A, B, by="ID")C$Flg <- if_else(is.na(C$Created.At), "N", "Y")
# ID Created.At Flg# 1 111 2018-10-31 06:25:20 Y# 2 222 2019-01-19 15:42:19 Y# 3 333 <NA> N# 4 444 2019-01-19 15:42:50 Y# 5 555 2020-06-30 22:04:54 Y# 6 666 <NA> N
英文:
library(dplyr)C <- left_join(A, B, by="ID")C$Flg <- if_else(is.na(C$Created.At), "N", "Y")# ID Created.At Flg# 1 111 2018-10-31 06:25:20 Y# 2 222 2019-01-19 15:42:19 Y# 3 333 <NA> N# 4 444 2019-01-19 15:42:50 Y# 5 555 2020-06-30 22:04:54 Y# 6 666 <NA> N
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