How do I create a copy of a data frame in R

Question

I want to duplicate the full contents of a data frame that has been read in from a *.csv file. I don't believe it is a duplication if I do copyOfFirstFrame <- firstFrame. So what do I need to do?

firstFrame <- read_csv("fileName.csv")
copyOfFirstFrame <- ?????

If I do the following the memory address remains the same.

copyOfFirstFrame <- firstFrame
tracemem(firstFrame) == tracemem(copyOfFirstFrame)
[1] TRUE

The copy must result in two unique memory addresses. Check In R, how can I check if two variable names reference the same underlying object? for details.

Answer 1

Let DATA be a pre-existing data frame object. I am creating a new object, COPY which is an exact copy of DATA, but it occupies a different memory location and hence doesn't point to the original data frame.

I use the function data.frame() like this:

> COPY<-data.frame(DATA)

I check whether the memory addresses are same or not using tracemem():

> tracemem(COPY)==tracemem(DATA)
> [1] FALSE

Lame enough, I think.

Answer 2

Using cbind with one data.frame will ensure you have a copy:

> df <- cbind(NA, NA)
> df2 <- cbind(df)
> df2
     [,1] [,2]
[1,]   NA   NA
> df2[,1] <- 1
> df
     [,1] [,2]
[1,]   NA   NA
> df2
     [,1] [,2]
[1,]    1   NA
>