[R] Confusion regarding environments invoked by "source" command

[Dennis Fisher]

Colleagues,

R version 2.8.1 in OS X

Within a function (which is already within a function), I am sourcing  
a file.  The syntax of the command is something like (this is just an  
example; the actual code is much more complicated):
BIGFUNCTION	<- function()
	{
	DATAFRAME	<- [some commands to create a dataframe]
	MYFUNCTION(DATAFRAME)
	}
MYFUNCTION	<- function(DATAFRAME)
	{
	print(ls())
	exists("DATAFRAME")
	source("myfile", local=T)
	}

The file "myfile" contains the following:
	print(DATAFRAME)

When I execute BIGFUNCTION from the command line, R reports:
	Error in print(DATAFRAME) : object "DATAFRAME" not found
	Calls: BIGFUNCTION ... source -> eval.with.vis -> eval.with.vis ->  
print -> head
	Execution halted
However, the "print(ls())" command has just listed the existence of  
DATAFRAME and "exists(DATAFRAME) return TRUE
So, I am at a loss as to why ls() and "exists" see the object but  
print(DATAFRAME) command does not.

I tried "local=F" in the source command to no avail.
I also replaced "print(DATAFRAME)" with "print(str(DATAFRAME))" with  
the same outcome.
I assume that this is an error as to how I am managing environments  
but I cannot figure out a solution.  Any help would be appreciated.

Dennis



Dennis Fisher MD
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