don't print object attributes

Tue, Aug 28, 2012 12:05 PM

On 28/08/2012 2:16 PM, Liviu Andronic wrote:

On Tue, Aug 28, 2012 at 7:34 PM, Duncan Murdoch
<murdoch.duncan at gmail.com> wrote:

Assign a class to the object, and write a print method for it.

For example, this doesn't quite do what you want, but it's a start:

print.noattributes <- function(x, ...) {
   attributes(x) <- NULL
   print(x)
}

class(x) <- "noattributes"
x

It loses some attributes that you probably want to keep (e.g. the names),
but otherwise works on your example.

I've already tried this solution but that's exactly the trouble with
this approach. Do this on a data.frame and loses important
information.

I came up with a modified version of the above:
print_noattr <- function(x, keep.some=T, ...){
     if(keep.some) xa <- attributes(x)[c('names', 'row.names', 'class')]
     attributes(x) <- NULL
     if(keep.some) attributes(x) <- xa
     print(x)
}

x <- dlply(iris, .(Species), function(x) describe(x[, 'Sepal.Length']))
print_noattr(x)

$setosa
x[, "Sepal.Length"]
       n missing  unique    Mean     .05     .10     .25     .50     .75
      50       0      15   5.006    4.40    4.59    4.80    5.00    5.20
     .90     .95
    5.41    5.61

           4.3 4.4 4.5 4.6 4.7 4.8 4.9  5 5.1 5.2 5.3 5.4 5.5 5.7 5.8
Frequency   1   3   1   4   2   5   4  8   8   3   1   5   2   2   1
%           2   6   2   8   4  10   8 16  16   6   2  10   4   4   2

$versicolor
x[, "Sepal.Length"]
       n missing  unique    Mean     .05     .10     .25     .50     .75
      50       0      21   5.936   5.045   5.380   5.600   5.900   6.300
     .90     .95
   6.700   6.755

lowest : 4.9 5.0 5.1 5.2 5.4, highest: 6.6 6.7 6.8 6.9 7.0

$virginica
x[, "Sepal.Length"]
       n missing  unique    Mean     .05     .10     .25     .50     .75
      50       0      21   6.588   5.745   5.800   6.225   6.500   6.900
     .90     .95
   7.610   7.700

lowest : 4.9 5.6 5.7 5.8 5.9, highest: 7.3 7.4 7.6 7.7 7.9


However this still feels like a hack, and the function should be
modified if the object in question contains some other crucial
attributes.

I think it's reasonable to say it feels like a hack, because it is. x 
should have had a class and a print method for that class in the first 
place, if the attributes are not something that users should see.  If 
they are things you should see, then suppressing them is a bad idea.

Duncan Murdoch

don't print object attributes

Thread (8 messages)