R help - Jun 2011 - Seeking help to define method for show() for an S4 object

Dear all, I have created a new S4 class with name "MyClass". Please
see
below for it's definition. Now I want to create a
method for the show() function for this class. In defining this method, what
I want is, once user would like see an object of this class
some values will be displayed. Then R will ask for **press Enter**. Once
user presses enter then, remaining values will be
displayed. In the following example, I try to explain this concept.

> setClass("MyClass", sealed = FALSE, representation(Slot1 =
"vector", Slot2
= "vector"))

[1] "MyClass"
> 
> setMethod("show", "MyClass", definition = function(x) {
+         cat("These are the values. Please press enter to see the
values.\n")

+         ####### User will presss the Enter ##########

+         ####### Then only following figures will be visible #########

+         cat(x@Slot1)

+        } )

[1] "show"

Warning message:

For function "show", signature "MyClass": argument in method
definition
changed from (x) to (object) 
> new("MyClass", Slot1 = 1:3, Slot2 = 4:7)
These are the values. Please press enter to see the values.

1 2 3>

 

 


Can somebody guide me how I can achieve that?


Thanks,

 


	[[alternative HTML version deleted]]

Hi,

Take a look at ?readLines  Also, you should use function(object) not
function(x) because of how the generic is defined.  Below is an
example.

Cheers,

Josh

setClass("MyClass", sealed = FALSE, representation(
  Slot1 = "vector",
  Slot2 = "vector"))

setMethod(f = "show", signature = "MyClass",
  definition = function(object) {
    cat("These are the values.  Please press enter to see the
values.\n")
    readLines(n = 1)
    cat(object at Slot1)
  })

x <- new("MyClass", Slot1 = 1:3, Slot2 = 4:7)
x

On Mon, Jun 6, 2011 at 10:19 AM, Bogaso Christofer
<bogaso.christofer at gmail.com> wrote:
> Dear all, I have created a new S4 class with name "MyClass".
Please see
> below for it's definition. Now I want to create a
> method for the show() function for this class. In defining this method,
what
> I want is, once user would like see an object of this class
> some values will be displayed. Then R will ask for **press Enter**. Once
> user presses enter then, remaining values will be
> displayed. In the following example, I try to explain this concept.
>
>
>> setClass("MyClass", sealed = FALSE, representation(Slot1 =
"vector", Slot2
> = "vector"))
>
> [1] "MyClass"
>
>>
>
>> setMethod("show", "MyClass", definition =
function(x) {
>
> + ? ? ? ? cat("These are the values. Please press enter to see the
> values.\n")
>
> + ? ? ? ? ####### User will presss the Enter ##########
>
> + ? ? ? ? ####### Then only following figures will be visible #########
>
> + ? ? ? ? cat(x at Slot1)
>
> + ? ? ? ?} )
>
> [1] "show"
>
> Warning message:
>
> For function "show", signature "MyClass": argument in
method definition
> changed from (x) to (object)
>
>> new("MyClass", Slot1 = 1:3, Slot2 = 4:7)
>
> These are the values. Please press enter to see the values.
>
> 1 2 3>
>
>
>
>
>
>
> Can somebody guide me how I can achieve that?
>
>
> Thanks,
>
>
>
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/