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print all variables inside function

4 messages · derek, Duncan Murdoch, Thierry Onkelinx +1 more

derek
# 
Hello dear R-help

I would like to use some short and simple names multiple times inside
one script without collisions. I need to wrap the variables inside
some object. I know I can use class function or environment. For
example as follows:

exmp1<-function(){

########
# knowns
pa=0.35
pb=0.35
pc=0.30
pad=0.015
pbd=0.010
pcd=0.020
########

########
# unknowns
pd=pa*pad+pb*pbd+pc*pcd
pdc=pc*pcd/pd
pda=pa*pad/pd
pba=pb*pbd/pd
########

y<-c(pad=pad,pbd=pbd,pcd=pcd,pd=pd,pdc=pdc,pda=pda,pba=pba) # this
line I would like to automate so I don't have to write it every time
return(y)
}
output<-exmp1()

Is it somehow possible to print 'Unknows' and 'Knowns' from exmp1
function without the need of explicitly write the 'y' line which puts
all variables inside list? For example with an imaginary function
'fprint' which takes exmp1 as the input: fprint(exmp1).
Duncan Murdoch
#
On 23/05/2016 3:26 PM, Jan Kacaba wrote:
Why create them first?  Just do something like this:

knowns <- c(
  pa=0.35
  pb=0.35
  pc=0.30
  pad=0.015
  pbd=0.010
  pcd=0.020)

Duncan Murdoch
Thierry Onkelinx
# 
Dear Jan,

This will return a list with all objects from within the function.

test <- function(){
  a <- 10
  b <- 3 * a + 1
  x <- -1
  output <- paste(objects(), objects(), sep = "=")
  output <- paste(output, collapse = ",")
  output <- paste("list(", output, ")")
  return(eval(parse(text = output)))
}
test()

Best regards,

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2016-05-23 21:26 GMT+02:00 Jan Kacaba <jan.kacaba at gmail.com>:

  
  


  


      

    

    

      
      

        


  

        

      William Dunlap
    

    

      
      #
    

  


  

      
If you really want to return all the objects in a function, I think it
is better to return as.list(environment()), perhaps adding the
all.names=TRUE argument to capture names starting with a dot.
I only have done this while debugging a function and then I
find it is more convenient to return just environment().

eval(parse(text="...")) will have problems when objects in the
environment have odd names, like 'Two words', '...', or '..1'.


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Mon, May 23, 2016 at 12:46 PM, Thierry Onkelinx <thierry.onkelinx at inbo.be