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[英]R: Count number of values from one column according to values in another column
[英]Find values from one column in another column according to ID in r
我有一個數據框,每個 ID 都有多個條目。 ID 有一個參考號 (NEW_REF) 和一個舊參考號 (OLD_REF)。 我需要為每個 ID 找到最新的參考號,這意味着舊參考號列中沒有的參考號。
ID <- c(1,2,3,4,1,3,5,2,4,1,3,4)
NEW_REF <- c("TS101","TS253","TS565","TS789","TD123","TS101","TD367","TH152","TD123","TF908","TD256","TS898")
OLD_REF <- c("TD123","TH152","TS101","TD123","TF908","TD256","TG232","TR142","TS898","TR268","TB496","TD969")
DF <- data.frame(ID,NEW_REF ,OLD_REF )
DF$Active_ind <- NA
DF$Active_ind[which(DF$NEW_REF %in% DF$OLD_REF )] <-"N" #if a reference number is in the old reference number column it is not active or not the most recent
DF$Active_ind[which(!(DF$NEW_REF %in% DF$OLD_REF ))] <-"Y" #if a reference number is not in the old reference number column it is active or the most recent
ID NEW_REF OLD_REF Active_ind
1 1 TS101 TD123 N
2 2 TS253 TH152 Y
3 3 TS565 TS101 Y
4 4 TS789 TD123 Y
5 1 TD123 TF908 N
6 3 TS101 TD256 N
7 5 TD367 TG232 Y
8 2 TH152 TR142 N
9 4 TD123 TS898 N
10 1 TF908 TR268 N
11 3 TD256 TB496 N
12 4 TS898 TD969 N
我的問題是 ID 1 有一個新的引用 TS101(第 1 行),而 ID 3 有一個舊的引用 TS101(第 3 行)。 如果參考編號不唯一,我如何檢查每個 ID哪個參考編號是最新的。
我希望第 1 行的 Active_ind 列中有一個 Y:
ID NEW_REF OLD_REF Active_ind
1 1 TS101 TD123 Y
2 2 TS253 TH152 Y
3 3 TS565 TS101 Y
4 4 TS789 TD123 Y
5 1 TD123 TF908 N
6 3 TS101 TD256 N
7 5 TD367 TG232 Y
8 2 TH152 TR142 N
9 4 TD123 TS898 N
10 1 TF908 TR268 N
11 3 TD256 TB496 N
12 4 TS898 TD969 N
我知道 for 循環是可能的,但我想避免它,因為我的數據集有超過 40 000 個不同的 ID,並且在使用循環時變得非常耗時。
我們可以使用dplyr
按ID
對它們進行分組,然后檢查OLD_REF
NEW_REF
,並相應地為它們提供值。
library(dplyr)
DF %>%
group_by(ID) %>%
mutate(Active_Ind = ifelse(NEW_REF %in% OLD_REF, "N", "Y"))
# ID NEW_REF OLD_REF Active_Ind
# <dbl> <fctr> <fctr> <chr>
# 1 TS101 TD123 Y
# 2 TS253 TH152 Y
# 3 TS565 TS101 Y
# 4 TS789 TD123 Y
# 1 TD123 TF908 N
# 3 TS101 TD256 N
# 5 TD367 TG232 Y
# 2 TH152 TR142 N
# 4 TD123 TS898 N
# 1 TF908 TR268 N
# 3 TD256 TB496 N
# 4 TS898 TD969 N
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