我有一个如下的数据集:
set.seed(1)
TDT <- data.table(Group = c(rep("A",40),rep("B",60)),
Id = c(rep(1,20),rep(2,20),rep(3,20),rep(4,20),rep(5,20)),
Time = rep(seq(as.Date("2010-01-03"), length=20, by="1 month") - 1,5),
norm = round(runif(100)/10,2),
y = sample(100,100),
x2 = round(rnorm(100,0.75,0.3),2),
x3 = round(rnorm(100,0.75,0.3),2),
x4 = round(rnorm(100,0.75,0.3),2),
x5 = round(rnorm(100,0.75,0.3),2))
我想用我选择的TDT
相关性创建一个新的数据集。为了获得因变量和选定的自变量(xcor
)与我尝试的所有其他自变量的相关性:
# getting the numerical variables
numcols <- names(Filter(is.numeric,TDT))
# getting the correlation of y with all x
TDT.y.cor<- TDT[, cor(.SD, y),.SDcols = numcols, by = Time]
# getting the correlation of selected x with all other x
xcor <- c("x2","x3")
TDT.x.cor <- TDT[, cor(.SD, xcor),.SDcols = numcols, by = Time]
但最后一个给出了错误:
Error in cor(.SD, xcor) :
'y' must be numeric
所以现在我想做一个for循环。类似于:
xcor <- list ("x2","x3")
for (i in xcor) {
TDT.xcor[[i]].cor <- TDT[, cor(.SD, xcor[[i]]),.SDcols = numcols, by = Time]
}
这不是正确的语法。有什么建议吗?
https://stackoverflow.com/questions/56671281
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