在R中，如何计算每个Deal_id的CustomerId数量？

Question

我有专栏：Deal_id，Customer_id

每个交易ID的多个客户ID。 我想添加一个列，其中包含每个交易ID的唯一客户数。我们怎么做？

Answer 1

对这个问题有点困惑，但这对你有用。

File = structure(list(DealID = c(99L, 99L, 99L, 99L, 11L, 11L, 11L, 
14L, 14L, 15L, 15L), CustomerID = c(1L, 3L, 3L, 4L, 5L, 6L, 7L, 
8L, 9L, 10L, 11L)), .Names = c("DealID", "CustomerID"), class = "data.frame", row.names = c(NA, 
-11L))

sqldf("Select DealID,count(*) as Total from File group by DealID")
File = unique(File)
sqldf("Select DealID,count(*) as Unique_Total from File group by DealID")