使用r中的条件语句将NA分配给行 [英] Assigning NAs to rows with conditional statement in r
问题描述
我正在尝试使用以下条件语句将NA分配给每个事件的前两行:如果每个事件的第一天的值都为"variable" = 0，请检查前一天.如果前一天(上一个事件的最后一天)的变量"> 0，则将NA分配给事件的前两行，且第一天的变量" = 0.如果前一天的变量" = 0，则不执行任何操作.
I'm trying to assign NAs to the first two rows of each event, with the following conditional statement: If the first day of each event has a value of "variable" = 0, check the day before. If the day before (last day of previous event) has a "variable" > 0, then assign NAs to the first two rows of the event having "variable" = 0 on the first day. If the day before has a "variable" = 0, do nothing.
这里是一个例子:
day <- c(1:16)
event<- c(1,1,2,3,4,4,4,5,5,5,6,6,6,7,7,7)
variable<- c(0,0,5,0,0,0,10,0,1,1,0,0,0,0,0,0)
A<- data.frame(day, event, variable)
day event variable
1 1 1 0
2 2 1 0
3 3 2 5
4 4 3 0
5 5 4 0
6 6 4 0
7 7 4 10
8 8 5 0
9 9 5 1
10 10 5 1
11 11 6 0
12 12 6 0
13 13 6 0
14 14 7 0
15 15 7 0
16 16 7 0
以及它的外观
day event variable
1 1 1 0
2 2 1 0
3 3 2 5
4 4 3 NA
5 5 4 0
6 6 4 0
7 7 4 10
8 8 5 NA
9 9 5 NA
10 10 5 1
11 11 6 NA
12 12 6 NA
13 13 6 0
14 14 7 0
15 15 7 0
16 16 7 0
注意:是否必须为事件1分配NA并不重要我尝试使用if条件执行此操作，但效果不佳.任何想法?并预先感谢！
Note: It doesn't matter if event 1 has to be assigned with NAs I tried to do this with if conditions, but is not working well. Any idea? and thanks in advance!
推荐答案
来自OP的新示例数据
library(data.table)
event2<- c(1,2,2,3,4,4,4,4,4,5,5)
variable2<- c(140, 0, 69, 569, 28, 0,0,0,100,0,0)
desire_output<- c(140, NA, NA, 569, 28, 0,0,0,100, NA,NA)
A2<- data.frame(event2, variable2, desire_output)
setDT(A2)
A2[,first_days_event:=fifelse(.I==min(.I),1,fifelse(.I==min(.I)+1,2,NA_integer_)),by=.(event2)]
A2[,result:={v <- variable2
for (i in 2:.N) {
if (is.na(first_days_event[i])) {
v[i] <- variable2[i]
} else if (first_days_event[i]==1 & variable2[i]==0){
if (variable2[i-1]>0) {
v[i] <- NA_integer_
if (first_days_event[i+1]==2) {
v[i+1] <- NA_integer_
}
}
}
}
v}]
A2
#> event2 variable2 desire_output first_days_event result
#> 1: 1 140 140 1 140
#> 2: 2 0 NA 1 NA
#> 3: 2 69 NA 2 NA
#> 4: 3 569 569 1 569
#> 5: 4 28 28 1 28
#> 6: 4 0 0 2 0
#> 7: 4 0 0 NA 0
#> 8: 4 0 0 NA 0
#> 9: 4 100 100 NA 100
#> 10: 5 0 NA 1 NA
#> 11: 5 0 NA 2 NA
我将使用这个简单的 loop 解决方案.只需创建一个标志来指示每个事件的前两天.
I will use this simple loop solution. Just need to create a flag indicating the first tow days of each event.
library(data.table)
day <- c(1:16)
event<- c(1,1,2,3,4,4,4,5,5,5,6,6,6,7,7,7)
variable<- c(0,0,5,0,0,0,10,0,1,1,0,0,0,0,0,0)
A<- data.frame(day, event, variable)
setDT(A)
A[,first_days_event:=fifelse(.I==min(.I),1,fifelse(.I==min(.I)+1,2,NA_integer_)),by=.(event)]
A[,result:={v <- numeric(.N)
for (i in 2:.N) {
if (is.na(first_days_event[i])) {
v[i] <- variable[i]
} else if (first_days_event[i]==1){
if (variable[i-1]>0) {
v[i] <- NA_integer_
if (first_days_event[i+1]==2) {
v[i+1] <- NA_integer_
}
} else {
v[i] <- variable[i]
}
}
}
v}]
A
#> day event variable first_days_event result
#> 1: 1 1 0 1 0
#> 2: 2 1 0 2 0
#> 3: 3 2 5 1 5
#> 4: 4 3 0 1 NA
#> 5: 5 4 0 1 0
#> 6: 6 4 0 2 0
#> 7: 7 4 10 NA 10
#> 8: 8 5 0 1 NA
#> 9: 9 5 1 2 NA
#> 10: 10 5 1 NA 1
#> 11: 11 6 0 1 NA
#> 12: 12 6 0 2 NA
#> 13: 13 6 0 NA 0
#> 14: 14 7 0 1 0
#> 15: 15 7 0 2 0
#> 16: 16 7 0 NA 0
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