[R] with lapply() how can you retrieve the name of the object

From: Andrew Yee <yee_at_post.harvard.edu>
Date: Fri, 18 Jul 2008 18:21:15 -0400


In the following code, I'd like to be able to create a new variable containing the value of the names of the list.

a <- data.frame(var.1 = 1:5)
b <- data.frame(var.1 = 11:15)

test.list <- list(a=a, b=b)

# in this case, names(test.list) is "a" and "b"

# and I'd like to use lapply() so that
# I get something that looks like
# var.1 var.2
# 1 a
# 2 a
# 3 a

#etc.

new.list <- lapply(test.list, function(x) {x$var.2 <- names(x)

                                            x} )


# the above clearly doesn't do it. How do you pull out the names of the
thing that is being lapplied?

Thanks,
Andrew

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