Converting Dataframe into List and inputting the function - r

Question

I have a dataset with different receipts, items and its value:
library(arules)
library(VennDiagram)
Data <- data.frame(
Receipt_ID = c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,5,5,6,6,6),
item = c('a','b','c','k','a','b','d','k','a','k','c','q','k', 'a','b','a','a', 'b', 'c'
)
,
value = c(2,3,2,4,2,5,6,7,8,1,2,3,4,5,6,7,8,3,4
)
)
And I created a market basket, with some output like below:
rules <- data.frame(
Target = c("a","a","b"),
item1 = c("b","b","k" )
,
item2 = c("k","",""),
lift = c(1,2,3),
confidence = c(0.08,0.45,0.1)
)
)
I created a function which will take the Vector of items as input(Combination of Target, item1, item2 in vector form)
findvalue <- function (vectormb) {
keyvalue <- Data[Data$item %in% vectormb, ]
keyvaluetran <- sapply(vectormb,function(x){
ret <- unique (keyvalue$Receipt_ID[keyvalue$item==x])
})
#reducetran <- calculate.overlap(keyvaluetran)
reducetran1 <- Reduce(intersect,keyvaluetran)
totalsales <- sum (keyvalue$value[keyvalue$Receipt_ID %in% reducetran1])
return(totalsales)
}
And I comverted the Dataframe to List
createlist <- function(data){
subset <- data.frame(data$Target,data$item1,data$item2)
listdata <- apply(subset,1,
function(x){
ret<-list( x[1:ncol(subset)])
names(ret)<-as.character(x[1])
return(ret)
})
listdata <- createlist(rules)
List data converts the dataframe to vector.
My question is how can I pass the Listdata Output to the function findvalue.
I tried couple of things:
findvalue(c("a","b","k")) is giving proper value as 23.
When I tried findvalue(listdata[1]), this is not giving any value.
What mistake I did. Listdata should be sent to findvalue in a loop.

Answer 1

Your createlist() function has no return value - hence it returns nothing for you. Here is what I would suggest:
createlist <- function(data) {
subset <- data.frame(data$Target,data$item1,data$item2)
apply(subset,1,
function(x){
ret<-list( x[1:ncol(subset)])
names(ret)<-as.character(x[1])
return(ret)
})
}
listdata <- createlist(rules)
This will create your listdata variable properly.
Then, in order to run findvalue() on it, the way the function is currently written, you need to pass on a vector, and not a list. Thus:
> class(listdata[1])
[1] "list"
> findvalue(unlist(listdata[1]))
[1] 23