[R] making chains from pairs
David Winsemius
dwinsemius at comcast.net
Sat Nov 9 09:55:25 CET 2013
On Nov 8, 2013, at 10:56 AM, Hermann Norpois wrote:
> Hello,
>
> having a data frame like test with pairs of characters I would like to
> create chains. For instance from the pairs A/B and B/I you get the vector A
> B I. It is like jumping from one pair to the next related pair. So for my
> example test you should get:
> A B F G H I
> C F I K
> D L M N O P
> second <- with(test, tapply(V2, V1, FUN=function(x) test[test$V2==x, ] ) )
Warning messages:
1: In test$V2 == x :
longer object length is not a multiple of shorter object length
2: In test$V2 == x :
longer object length is not a multiple of shorter object length
3: In test$V2 == x :
longer object length is not a multiple of shorter object length
> third <- sapply(names(second) , function(df) c(df, second[[df]][ , "V2" ]) )
> third
$A
[1] "A" "B" "F" "G" "H"
$B
[1] "B" "F" "I" "F" "I"
$C
[1] "C" "F" "I" "K"
$D
[1] "D" "L" "M" "N"
$L
[1] "L" "O" "P"
> fourth <- sapply(names(third), function(d) unique( c(third[[d]],
unlist(third[ sapply( third[[d]], "[" ) ]) ) ) )
> fourth
$A
[1] "A" "B" "F" "G" "H" "I"
$B
[1] "B" "F" "I"
$C
[1] "C" "F" "I" "K"
$D
[1] "D" "L" "M" "N" "O" "P"
$L
[1] "L" "O" "P"
>
>
>> test
> V1 V2
> 1 A B
> 2 A F
> 3 A G
> 4 A H
> 5 B F
> 6 B I
> 7 C F
> 8 C I
> 9 C K
> 10 D L
> 11 D M
> 12 D N
> 13 L O
> 14 L P
>
> Thanks
> Hermann
>
>> dput (test)
> structure(list(V1 = c("A", "A", "A", "A", "B", "B", "C", "C",
> "C", "D", "D", "D", "L", "L"), V2 = c("B", "F", "G", "H", "F",
> "I", "F", "I", "K", "L", "M", "N", "O", "P")), .Names = c("V1",
> "V2"), row.names = c(NA, -14L), class = "data.frame")
>>
>
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>
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David Winsemius
Alameda, CA, USA
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