CODEWITHSUNDEEP
rcombinationscombinatorics
Plantekös
Plantekös

Reputation: 33

Dataframe with combinatorial data and conditions

I am looking for how to transform a dataframe with combinatorial data and conditions in r.

To be clear, this is my first dataframe :

| x1 A |
| x1 B |
| x1 C |
| x2 A |
| x2 B |

And I would like this :

| x1 A B |
| x1 A C |
| x1 B C |
| x2 A B |

I have started to write code but I am not familiar with the required loops. Indeed, I managed to write the part for one condition(let's say "X1") but I don't know how to create the whole table.

This is where I am :

# Initiate data frame :
a <- c('x1','A')
b <- c('x1','B')
c <- c('x1','C')
d <- c('x2','D')
matrix <- matrix(c(a,b,c,d),nrow=4,ncol=2,byrow=T)
colnames(matrix) <- c("Patent","Class")

# Combine :
temp <- matrix %>%
  filter(Patent == 'x1') %>%
  select (Class)
temp <- as.vector(t(temp))
temp2 <- t(combn(temp,2))
temp2

# Associate condition :

vector <- rep("x1",nrow(temp2))
vector
temp3 <- cbind(vector,temp2)
temp3

Upvotes: 0

Views: 63

Answers (1)

chinsoon12
chinsoon12

Reputation: 25225

Using data.table and generating combination of 2 elements using combi :

DT[, transpose(combn(Class, 2L, simplify=FALSE)), by=.(Patent)]

output:

   Patent V1 V2
1:     x1  A  B
2:     x1  A  C
3:     x1  B  C
4:     x2  A  B

data:

library(data.table)
DT <- data.table(Patent=c(rep("x1", 3), rep("x2", 2)), Class=c(LETTERS[1:3], LETTERS[1:2]))

Upvotes: 1

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