pachamaltese - 1 year ago 76
R Question

# How to count common concepts and store the result in a matrix?

I want/need to create a matrix of 1's and 0's that contains the information about common terms. I created a matrix of common terms between columns (e.g. with rows like 1,4,2) but I do not figure out how to disaggregate it.

Here is a toy and reproducible example. Steps (1)-(4) are ok and step (5) is what I cannot do at the moment.

(1) I have this (fictional) dataset

``````vec1 <- c("apple","pear","apple and pear")
vec2 <- c("apple and pear","banana","orange")
vec3 <- c("orange and pear","banana","apple")

my.data.frame <- as.data.frame(cbind(vec1,vec2,vec3))

vec1           vec2            vec3
1          apple apple and pear orange and pear
2           pear         banana          banana
3 apple and pear         orange           apple
``````

(2) I extract the variables and the content

``````vectors.list <- as.vector(colnames(my.data.frame))

list.of.fruits <- unique(as.vector(unlist(my.data.frame)))
``````

(2) I write down a function to count common terms (this is a deformation of this post: How to count common words and store the result in a matrix?)

``````common.fruits <- function(vList) {
v <- lapply(vList, tolower)
do.call(rbind, lapply(v, function(x) {
do.call(c, lapply(v, function(y) length(intersect(x, y))))
}))
}
``````

(4) I use get and lapply to do some efficient (I guess) calculation

``````compare <- lapply(vectors.list,get)
common.terms.matrix <- common.fruits(compare)
rownames(common.terms.matrix) <- vectors.list
colnames(common.terms.matrix) <- vectors.list
common.terms.matrix

vec1 vec2 vec3
vec1    3    1    1
vec2    1    3    1
vec3    1    1    3
``````

(5) How do I disaggregate that last matrix into this matrix or data.frame (the "|" are to indicate that this was written by hand)

``````     | apple | pear | apple and pear | banana | orange | orange and pear
vec1 | 1     | 1    | 1              | 0      | 0      | 0
vec2 | 0     | 0    | 1              | 1      | 1      | 0
vec3 | 1     | 0    | 0              | 1      | 0      | 1
``````

You can try something like the following:

``````my.data.frame\$id <- 1:nrow(my.data.frame)
m <-  melt(my.data.frame, id='id')
m\$val <- 1
df <- dcast(m, variable~value, value.var='val')
df[is.na(df)] <- 0

df
variable apple apple and pear banana orange orange and pear pear
1     vec1     1              1      0      0               0    1
2     vec2     0              1      1      1               0    0
3     vec3     1              0      1      0               1    0
``````
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