如何在 R 中使用 get() 来访问带有另一个变量的变量？

Question

I have a loop which is running over a vector containing names of a few tens of dataframes that are in my environment. On each iteration, I want to access the dataframe using the name, and access a specific column within it. As I understand it, the best way to access a variable with a string is using get() .

But when I try and do this (with name being a variable containing the string "first.name" ):

get(column.name, name)

I get the error:

Error in as.environment(pos) : no item called "first.name" on the search list

It does work if I try to run:

get(column.name, first.name)

So, assuming that get() is the right function for this, what am I doing wrong?

Reproduceable example:

my.df <- as.data.frame(x = seq(1:10), y = rnorm(10))

name <- "my.df"
get("x",name)

Answer 1

We may need to use

get(name)[[column.name]]