CODEWITHSUNDEEP
r
Fr.
Fr.

Reputation: 2885

Extract each column of a data frame into an object

I have a data frame with many columns, named foo, bar, etc.

I would like to extract each column of the data frame to separate objects called foo, bar and so on. Is there an automated way to do this in R?

Working example:

mock <- structure(list(
x = structure(1:3, .Label = c("1", "2", "3"), class = "factor"), 
y = structure(1:3, .Label = c("A", "B", "C"), class = "factor"), 
z = structure(c(1L, 1L, 2L), .Label = c("0", "1"), class = "factor")), 
.Names = c("x", "y", "z"), row.names = c(NA, -3L), class = "data.frame")

Output:

> mock
  x y z
1 1 A 0
2 2 B 0
3 3 C 1

How can I write a loop that creates objects x, y and z from the three columns of this data frame?

Upvotes: 2

Views: 280

Answers (1)

Jonathan Christensen
Jonathan Christensen

Reputation: 3866

> for (i in 1:ncol(mock)) {
+   assign(names(mock)[i],mock[,i])
+ }
> x
[1] 1 2 3
Levels: 1 2 3
> y
[1] A B C
Levels: A B C
> z
[1] 0 0 1
Levels: 0 1

You should be careful with the use of assign, though. You can achieve almost the same result using attach(mock), which is reversible (detach()) and won't unintentionally overwrite existing variables (it just masks them).

Upvotes: 2

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