[英]subsetting a dataframe into a vector based upon a row value of another column in R
[英]Create a column that assigns value to a row in a dataframe based on an event in another row
我有一個結構如下的數據框:
example <- data.frame(id = c(1,1,1,1,1,1,1,2,2,2,2,2),
event = c("email","email","email","draw","email","email","draw","email","email","email","email","draw"),
date = c("2020-03-01","2020-06-01","2020-07-15","2020-07-28","2020-08-07","2020-09-01","2020-09-15","2020-05-22","2020-06-15","2020-07-13","2020-07-15","2020-07-31"),
amount = c(NA,NA,NA,10000,NA,NA,1500,NA,NA,NA,NA,2200))
這是數據框的簡化版本。 我正在嘗試創建一個列,該列將在繪制事件之前為最后一封電子郵件分配一個 1,以及一個將在與電子郵件相同的行上繪制的金額的列。 所需的數據框如下所示:
desiredResult <- data.frame(id = c(1,1,1,1,1,1,1,2,2,2,2,2),
event = c("email","email","email","draw","email","email","draw","email","email","email","email","draw"),
date = c("2020-03-01","2020-06-01","2020-07-15","2020-07-28","2020-08-07","2020-09-01","2020-09-15","2020-05-22","2020-06-15","2020-07-13","2020-07-15","2020-07-31"),
amount = c(NA,NA,NA,10000,NA,NA,1500,NA,NA,NA,NA,2200),
EmailBeforeDrawFlag = c(NA,NA,1,NA,NA,1,NA,NA,NA,NA,1,NA),
EmailBeforeDrawAmount = c(NA,NA,10000,NA,NA,1500,NA,NA,NA,NA,2200,NA))
這是dplyr
解決方案。 當你創建新列,要使用if_else()
中的定義EmailBeforeDrawFlag
檢驗一個條件,而lead
功能上一行去尋找event
。 EmailBeforeDrawAmount
是突出的lead(amount)
。
example %>%
mutate(EmailBeforeDrawFlag = if_else(lead(event) == "draw", 1, NA_real_ ),
EmailBeforeDrawAmount = lead(amount))
id event date amount EmailBeforeDrawFlag EmailBeforeDrawAmount
1 1 email 2020-03-01 NA NA NA
2 1 email 2020-06-01 NA NA NA
3 1 email 2020-07-15 NA 1 10000
4 1 draw 2020-07-28 10000 NA NA
5 1 email 2020-08-07 NA NA NA
6 1 email 2020-09-01 NA 1 1500
7 1 draw 2020-09-15 1500 NA NA
8 2 email 2020-05-22 NA NA NA
9 2 email 2020-06-15 NA NA NA
10 2 email 2020-07-13 NA NA NA
11 2 email 2020-07-15 NA 1 2200
12 2 draw 2020-07-31 2200 NA NA
我們還可以利用NA^
在lead
上創建列
library(dplyr)
example %>%
mutate(EmailBeforeDrawFlag = NA^(lead(event != 'draw')),
EmailBeforeDrawAmount = lead(amount))
-輸出
# id event date amount EmailBeforeDrawFlag EmailBeforeDrawAmount
#1 1 email 2020-03-01 NA NA NA
#2 1 email 2020-06-01 NA NA NA
#3 1 email 2020-07-15 NA 1 10000
#4 1 draw 2020-07-28 10000 NA NA
#5 1 email 2020-08-07 NA NA NA
#6 1 email 2020-09-01 NA 1 1500
#7 1 draw 2020-09-15 1500 NA NA
#8 2 email 2020-05-22 NA NA NA
#9 2 email 2020-06-15 NA NA NA
#10 2 email 2020-07-13 NA NA NA
#11 2 email 2020-07-15 NA 1 2200
#12 2 draw 2020-07-31 2200 NA NA
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