將COL值分配給在不同列中觀察到的第一，第二，第三個值

Question

我對患者ID和他們是否經歷過干預的二元指標有一個df。我想創建一個名爲「time_post」的新列，它告訴我經歷了干預後有多少時間點已經過去。

這裏是我的DF：

names<-c("tom","tom","tom","tom","tom","tom","tom","tom", "john", "john","john", "john","john", "john","john", "john") 
post<-as.numeric(0,0,0,1,1,1,1,1,0,1,1,1,1,1,1,1) 
df<-data.frame(names,post) 

這是我曾嘗試：

df$time_post<-ifelse(df$post==1[1],1,0) ##this tries to assign 1 to "time_post" for first value of 1 seen in post 

df$time_post<-ifelse(df$post==1[2],2,df$time_post) ##trying to apply same logic here, but doesn't work. Introduces NAs into time_post column. 

這是我想要的輸出;

names post time_post 
1 tom 0   0 
2 tom 0   0 
3 tom 0   0 
4 tom 1   1 
5 tom 1   2 
6 tom 1   3 
7 tom 1   4 
8 tom 1   5 
9 john 0   0 
10 john 1   1 
11 john 1   2 
12 john 1   3 
13 john 1   4 
14 john 1   5 
15 john 1   6 
16 john 1   7 

預先感謝您

Answer 1

試試這個：

df<-data.frame(names=c("tom","tom","tom","tom","tom","tom","tom","tom", 
         "john", "john","john", "john","john", "john","john", "john"), 
       post=c(0,0,0,1,1,1,1,1,0,1,1,1,1,1,1,1)) 
df$time_post <- with(df, ave(post,names,FUN=cumsum)) 

它給你：

> df 
    names post time_post 
1 tom 0   0 
2 tom 0   0 
3 tom 0   0 
4 tom 1   1 
5 tom 1   2 
6 tom 1   3 
7 tom 1   4 
8 tom 1   5 
9 john 0   0 
10 john 1   1 
11 john 1   2 
12 john 1   3 
13 john 1   4 
14 john 1   5 
15 john 1   6 
16 john 1   7