我有一个data.table
包含指定唯一情况的多个列的对象。在下面的小例子中,变量“name
", "job
", and "sex
“指定唯一的 ID。我想添加缺失的行,以便每个案例对于另一个变量的每个可能实例都有一行,”from
“ (如同expand.grid
).
library(data.table)
set.seed(1)
mydata <- data.table(name = c("john","john","john","john","mary","chris","chris","chris"),
job = c("teacher","teacher","teacher","teacher","police","lawyer","lawyer","doctor"),
sex = c("male","male","male","male","female","female","male","male"),
from = c("NYT","USAT","BG","TIME","USAT","BG","NYT","NYT"),
score = rnorm(8))
setkeyv(mydata, cols=c("name","job","sex"))
mydata[CJ(unique(name, job, sex), unique(from))]
这是当前的 data.table 对象:
> mydata
name job sex from score
1: john teacher male NYT -0.6264538
2: john teacher male USAT 0.1836433
3: john teacher male BG -0.8356286
4: john teacher male TIME 1.5952808
5: mary police female USAT 0.3295078
6: chris lawyer female BG -0.8204684
7: chris lawyer male NYT 0.4874291
8: chris doctor male NYT 0.7383247
这是我想要的结果:
> mydata
name job sex from score
1: john teacher male NYT -0.6264538
2: john teacher male USAT 0.1836433
3: john teacher male BG -0.8356286
4: john teacher male TIME 1.5952808
5: mary police female NYT NA
6: mary police female USAT 0.3295078
7: mary police female BG NA
8: mary police female TIME NA
9: chris lawyer female NYT -NA
10: chris lawyer female USAT -NA
11: chris lawyer female BG -0.8204684
12: chris lawyer female TIME -NA
13: chris lawyer male NYT 0.4874291
14: chris lawyer male USAT NA
15: chris lawyer male BG NA
16: chris lawyer male TIME NA
17: chris doctor male NYT 0.7383247
18: chris doctor male USAT NA
19: chris doctor male BG NA
20: chris doctor male TIME NA
这是我尝试过的:
setkeyv(mydata, cols=c("name","job","sex"))
mydata[CJ(unique(name, job, sex), unique(from))]
但我收到以下错误并添加 fromLast=TRUE (或 FALSE) 并没有给我正确的解决方案:
Error in unique.default(name, job, sex) :
'fromLast' must be TRUE or FALSE
以下是我遇到的相关答案(但似乎没有一个答案涉及多个键控列):将缺失的行添加到数据表中 https://stackoverflow.com/questions/22462405/add-missing-rows-to-a-data-table
在 data.table 中高效插入默认缺失行 https://stackoverflow.com/questions/16518505/efficiently-inserting-default-missing-rows-in-a-data-table
在 data.frame 中添加缺失值行的最快方法? https://stackoverflow.com/questions/10438969/fastest-way-to-add-rows-for-missing-values-in-a-data-frame