相关疑难解决方法(0)

一些玩具数据

set.seed(123)
df <- data.frame(what_ever = rnorm(5, 50, 1),
                 this_is = rnorm(5, 30, 1),
                 wtf_nnn = rnorm(5, 20, 1),
                 hat_ever = rnorm(5, 50, 1),
                 who_is = rnorm(5, 30, 1),
                 mmm_nnn = rnorm(5, 20, 1)                 
                 )


library(data.table)
DT <- data.table(df)

str(DT)
Classes ‘data.table’ and 'data.frame':  5 obs. of  6 variables:

如何data.table 使用循环生成以下结果的新变量？

New_Var_1 = what_ever/hat_ever
New_Var_2 = this_is/who_is
New_Var_3 = wtf_nnn/mmm_nnn

在这里,我订购列名称

nm <- names(df)
nm1 <- nm[1:3]
nm2 <- nm[4:6]

我想以这种方式更新DT,并循环通过

i <- 1

New_Var_names <- paste("New_Var_", i, sep …