[R] do.call invoking a function with multiple arguments

[Dimitris Rizopoulos]

Hi Eric,

you could try it this way:

> tab <- as.data.frame(table(factor(1:10)))
> do.call("paste", c(tab, list(sep=":")))
 [1] "1:1"  "2:1"  "3:1"  "4:1"  "5:1"  "6:1"  "7:1"  "8:1"  "9:1" 
"10:1"


since `tab' is already a list

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Eric Lecoutre" <lecoutre at stat.ucl.ac.be>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, November 09, 2004 9:12 AM
Subject: [R] do.call invoking a function with multiple arguments


>
> Hi users,
>
> I am not sure to understand the help page about do.call.
>
> --
>  do.call(what, args)
>     args: a _list_ of arguments to the function call.  The 'names'
>           attribute of 'args' gives the argument names.
> --
>
> If we take the following sample data:
>
>
> > (tab=as.data.frame(table(factor(1:10))))
>    Var1 Freq
> 1     1    1
> 2     2    1
> 3     3    1
> 4     4    1
> 5     5    1
> 6     6    1
> 7     7    1
> 8     8    1
> 9     9    1
> 10   10    1
>
> I can call "paste" on it:
>
> > do.call("paste",tab)
>  [1] "1 1"  "2 1"  "3 1"  "4 1"  "5 1"  "6 1"  "7 1"  "8 1"  "9 1" 
> "10 1"
>
> Now if I want to use ":" as the separator, I guess I should write
>
> > do.call("paste",list(tab,sep=":"))
> [1] "c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)" "c(1, 1, 1, 1, 1, 1, 1, 1, 1, 
> 1)"
>
> which does not return me what I want.
> Of course, I know there are plenty other ways to achieve my goal but 
> this is not the first case I encounter I cant' use "do.call" though 
> I think it should be possible.
>
> Could someone bring me an example of such a use?
> basically, my needs are:
>
> do.call("foo",args) args containing primary and extra-arguments to 
> pass to "foo".
>
> Best wishes,
>
> Eric
>
>
> Eric Lecoutre
> UCL /  Institut de Statistique
> Voie du Roman Pays, 20
> 1348 Louvain-la-Neuve
> Belgium
>
> tel: (+32)(0)10473050
> lecoutre at stat.ucl.ac.be
> http://www.stat.ucl.ac.be/ISpersonnel/lecoutre
>
> If the statistics are boring, then you've got the wrong 
> numbers. -Edward Tufte
>
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