arules包-准备数据

Question

我如何准备“事务”形式的数据，但对于每个事务ID，时间影响/顺序都被考虑在内？我发现使用"split“函数，它们将按字母顺序排序。

例如：

ID Items Sequence
1  D     1
1  A     2
1  C     3
2  A     1 
2  B     2

事务中的期望输出：

ID Items
1  D A C #notice that A comes after D as it is dictacted by sequence variable 
        #                                                        here for the order
2  A B

致以问候。

Answer 1

使用lapply和rbind，

DF = read.table(text="ID Items Sequence
1  D     1
1  A     2
1  C     3
2  A     1 
2  B     2",header=TRUE,stringsAsFactors=FALSE,na.strings="")


DF
#  ID Items Sequence
#1  1     D        1
#2  1     A        2
#3  1     C        3
#4  2     A        1
#5  2     B        2

对于每个ID，将dataframe子集，按顺序排序，组合项目，并返回每个ID的输出

DF_new = do.call(rbind,lapply(unique(DF$ID),function(x) {

subset_DF = DF[DF$ID==x,];
subset_DF = subset_DF[,order(subset_DF$Sequence)]
subset_DF = subset_DF[,c("ID","Items")]
subset_DF$Items = paste0(subset_DF$Items,collapse=" ")
subset_DF = unique(subset_DF)
rownames(subset_DF)= NULL
return(subset_DF)
}))

DF_new
#  ID Items
#1  1 D A C
#2  2   A B