Arules Sequence Mining in R

问题

I am looking to use the arulesSequences package in R. However, I have no idea as to how to coerce my data frame into an object that can leverage this package.

Here is a toy dataset that replicates my data structure:

ids <- c(rep("X", 5), rep("Y", 5), rep("Z", 5))
seq <- rep(1:5,3)
val <- sample(LETTERS, 15, replace=T)
df <- data.frame(ids, seq, val)
df

   ids seq val
1    X   1   T
2    X   2   H
3    X   3   V
4    X   4   A
5    X   5   X
6    Y   1   D
7    Y   2   B
8    Y   3   A
9    Y   4   D
10   Y   5   P
11   Z   1   Q
12   Z   2   R
13   Z   3   W
14   Z   4   W
15   Z   5   P

Any help will be greatly appreciated.

回答1:

Factor data frame:

df_fact = data.frame(lapply(df,as.factor))

Build "transaction" data:

df_trans = as(df_fact, 'transactions')

Test it:

itemFrequencyPlot(df_trans, support = 0.1, cex.names=0.8)

回答2:

By using read_baskets:

    read_baskets(con  = filePath.txt,
      sep = " ",
      info = c("sequenceID","eventID","SIZE"))

Which in practice means exporting the created data to a text-file and re-importing it through read_baskets. The info argument defines the first columns containing the sequenceID, eventID and an optional eventsize column.

回答3:

It worked for me add an essentially "order" column that lists a order ranking rather than a time value. You just have to be very specific in the naming convention. Try and name the "group" or "ordered basket #" variable sequenceID, and call the ranking or ordering eventID.

Another thing that helped me (and had me scratching my head for a long time) was that read_baskets() seemed to need me to specify

read_baskets(con  = filePath.txt, sep = " ", info = c("sequenceID","eventID","SIZE"))

Even though the help function makes the c() details seem like an optional header, it is not. I seemed to need to remove the header from my file and specify it in the read_baskets() command, or I'd run into problems.

回答4:

Instead of using the data frame, what worked best for me was to split the data into individual and than convert to transactions.

 eh$cost<-split(eh$cost$val ,eh$cost$id)
 eh$cost1<- as(eh$cost,"transactions")

回答5:

You have to first change your items into transactions so just coerce the column of items
trans = as(df[,'val'], "transactions")

then you can add the information to your transactions object

trans@itemsetInfo$transactionID = NULL trans@itemsetInfo$sequenceID = df$ids trans@itemsetInfo$eventID = df$seq

来源：https://stackoverflow.com/questions/13022102/arules-sequence-mining-in-r

标签

arules