Get list of available data frames

Question

How do I get vector of data frame names available in current environment? I've tried:

sapply(ls(), is.data.frame)

But this fails because ls returns vector of strings. I'm planning to use this list as a input for dynamic selection in Shiny app.

Answer 1

You can use eapply to loop through the objects in an environment:

x <- 1:10
y <- mtcars
eapply(.GlobalEnv,is.data.frame)
$x
[1] FALSE

$y
[1] TRUE

names(which(unlist(eapply(.GlobalEnv,is.data.frame))))
[1] "y"

Answer 2

I think you're asking for the actual names of these data frames rather than the data frames themselves? You can do:

l <- ls()
l[sapply(l, function(x) is.data.frame(get(x)))]

get() will return the value of an object given a character name.

---

Tidier way of doing basically the same thing:

Filter(function(x) is.data.frame(get(x)), ls())

Answer 3

You need get, try this:

x <- sapply(sapply(ls(), get), is.data.frame)
names(x)[(x==TRUE)]