[R] find the data frames in list of objects and make a list of them

Matthew mccormack at molbio.mgh.harvard.edu
Thu Aug 14 00:49:51 CEST 2014

Hi Richard,

     Thank you very much for your reply and your code.
Your code is doing just what I asked for, but does not seem to be what I 

I will need to review some basic R before I can continue.

I am trying to list data frames in order to bind them into 1 single data 
frame with something like: dplyr::rbind_all(list of data frames), but 
when I try dplyr::rbind_all(lsDataFrame(ls())), I get the error: object 
at index 1 not a data.frame. So, I am going to have to learn some more 
about lists in R before proceding.

Thank you for your help and code.



On 8/13/2014 3:12 PM, Richard M. Heiberger wrote:
> I would do something like this
> lsDataFrame <- function(xx=ls()) xx[sapply(xx, function(x)
> is.data.frame(get(x)))]
> ls("package:datasets")
> lsDataFrame(ls("package:datasets"))
> On Wed, Aug 13, 2014 at 2:56 PM, Matthew
> <mccormack at molbio.mgh.harvard.edu> wrote:
>> Hi everyone,
>>     I would like the find which objects are data frames in all the objects I
>> have created ( in other words in what you get when you type: ls()  ), then I
>> would like to make a list of these data frames.
>> Explained in other words; after typing ls(), you get the names of objects.
>> Which objects are data frames ?  How to then make a list of these data
>> frames.
>>     A second question: is this the best way to make a list of data frames
>> without having to manually type c(dataframe1, dataframe2, ...)  ?
>> Matthew
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