[R] How to make a cartesian pairlist from a vector?

[Charles C. Berry]

On Fri, 20 Nov 2009, newbyr wrote:

>
> Hi,
>
> I'm looking for a function that will take a list of columns or data.frame
> and corvert it to cartesian pairlist. For example for this data.frame (see
> below), I'd like to get a list of all possible pairs:
>
>> sound
>  cs rs ns
>  7  5  2
>  4  5  4
>  6  3  1
>  8  4  1
>  6  4  2
>  6  7  1
>  2  2  5
>  9  2  5
>

> how can I get this?
>> mylist
>  ((cs,rs), (cs,ns), (rs,ns))

 	str(combn(colnames(df),2,function(x) df[,x],simplify=F))

see

 	?combn

HTH,

Chuck

p.s. Following the posting guide's hints you might try

?combinations  # no go, but it says try ??combinations
??combinations # shows utils:combn
?combn #  bingo!




>
> This list contains a set of all possible combinations of column pairs.
>
> Thank you for your help.
>
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>
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>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901