Reshape dataframe and create similarity matrix - r

Question

I have a data table, and I try Reshaping it but it doesn't work, how do I do this:
I have a data table:
Name | Value
-------------
Bob | 8,9,10
------------
Mike | 2,3,4
------------
Sandr| 5,6,7
How do I make this into a list like:
Value | Name
-------------
2 | Mike
3 | Mike
4 | Mike
5 | Sandr
6 | Sandr
7 | Sandr
8 | Bob
9 | Bob
10 | Bob
And then make this list into a matrix like:
2 3 4 5 6 7 8 9 10
-------------------
2 | 1 1 1 0 0 0 0 0 0
3 | 1 1 1 0 0 0 0 0 0
4 | 1 1 1 0 0 0 0 0 0
5 | 0 0 0 1 1 1 0 0 0
6 | 0 0 0 1 1 1 0 0 0
7 | 0 0 0 1 1 1 0 0 0
8 | 0 0 0 0 0 0 1 1 1
9 | 0 0 0 0 0 0 1 1 1
10| 0 0 0 0 0 0 1 1 1

Answer 1

The functions you are looking for are stack and contrasts.
data<-list(bob=c(8,9,10),mike=c(2,3,4),sandr=c(5,6,7))
as.data.frame(data)
bob mike sandr
1 8 2 5
2 9 3 6
3 10 4 7
stack(data)
values ind
1 8 bob
2 9 bob
3 10 bob
4 2 mike
5 3 mike
6 4 mike
7 5 sandr
8 6 sandr
9 7 sandr
df<-stack(data)
contrasts(df$ind,contrasts=FALSE)[df$ind,df$ind]
bob bob bob mike mike mike sandr sandr sandr
bob 1 1 1 0 0 0 0 0 0
bob 1 1 1 0 0 0 0 0 0
bob 1 1 1 0 0 0 0 0 0
mike 0 0 0 1 1 1 0 0 0
mike 0 0 0 1 1 1 0 0 0
mike 0 0 0 1 1 1 0 0 0
sandr 0 0 0 0 0 0 1 1 1
sandr 0 0 0 0 0 0 1 1 1
sandr 0 0 0 0 0 0 1 1 1
You can assign row names and column names and sort if desired
im<-contrasts(df$ind,contrasts=FALSE)[df$ind,df$ind]
rownames(im)<-df$values
colnames(im)<-df$values

Answer 2

res <- read.table(text="Name | Value
Bob | 8,9,10
Mike | 2,3,4
Sandr| 5,6,7", header=TRUE, sep="|")
dres <- data.frame(Value= unlist( strsplit(as.character(res$Value), ",") )
, Name=rep(res$Name, each=3))
dres <- dres[order(as.numeric(as.character(dres$Value))), ]
dres
outer(sort(dres$Value), sort(dres$Value), FUN=function(x,y) dres[x, "Name"] == dres[y,"Name"] )
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