Display the structure of an exdf object
str.exdf.RdDisplays the structure of an exdf object's main_data. Each
  column is described by its name, unit, and category formatted like
  name [category] (units).
Usage
# S3 method for class 'exdf'
str(object, ...)Examples
simple_exdf <- exdf(data.frame(A = 1), data.frame(A = 'u'), data.frame(A = 'c'))
str(simple_exdf)
#> 
#> Converting an `exdf` object to a `data.frame` before printing
#> 
#> 'data.frame':	1 obs. of  1 variable:
#>  $ A [c] (u): num 1