R：创建新列，名称来自变量 [英] R: create new column with name coming from variable

问题描述

我有一个包含几列的数据框，并想添加一个新列并根据以前的变量将其命名。例如：

I have a dataframe with several columns and would like to add a new column and name it according to a previous variable. For example:

df <- data.frame("A" = c(1, 2, 3, 4), "B" = c("a", "c", "d", "b"))
Variable <- "C"

这是函数的一部分，变量将在其中更改，而不是每次都指定：

This is part of a function where the variable will be changing and rather than each time specifying:

df$C <- NA

我想一行以变量命名为附加列

I would like a one line that will take the "Variable" to name the additional column

推荐答案

尝试 [而不是 $ ：

> df[, Variable] <- NA
> df
  A B  C
1 1 a NA
2 2 c NA
3 3 d NA
4 4 b NA

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