[R] Symbolic references - passing variable names into functions

Alexander Shenkin ashenkin at ufl.edu
Wed Aug 12 16:27:09 CEST 2009


Hello All,

I am trying to write a function which would operate on columns of a
dataframe specified in parameters passed to that function.

    f = function(dataf, col1 = "column1", col2 = "column2") {
        dataf$col1 = dataf$col2 # just as an example
    }

The above, of course, does not work as intended.  In some languages one
can force evaluation of a variable, and then use that evaluation as the
variable name.  Thus,

    > a = "myvar"
    > (operator)a = 1
    > myvar
    [1] 1

Is there some operator which allows this symbolic referencing in R?

Thanks,
Allie




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