list - Finding the names of all the columns in all the dataframes in a workspace -

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Assume that I have several data frames in a workspace in R and I want a list of column names in all data frames. .

I thought the following would work. But this is not to see it in your own workspace. 

  sapply (ls (), name)   
 Why does not this work? LS () creates a list of all data frames and then the name function should be applied on each data frame. This is a simple question for me now.  
 Coming forward: I want to determine all those columns whose names are with them, so that I can apply the following for each of them. Columns do not matter what they do The data are in the frame.  
  as.Date (dataframe $ dateofenrollment, origin = "1899-12-30")    
 
 
 This does not work because  ls ()  returns the object names in our workspace, not the objects themselves  
 You probably want something like the following:  
  lapply (ls (), function (x) if (is.data.frame (o   
 There will be  NULL  elements for any object that is not data frames but you can possibly work around it / P>

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