有条件地计入dplyr

Question

我有一些会员订单数据,我想按订单周汇总.

这就是数据的样子:

memberorders=data.frame(MemID=c('A','A','B','B','B','C','C','D'),
             week = c(1,2,1,4,5,1,4,1),
             value = c(10,20,10,10,2,5,30,3))

我正在使用dplyr来group_by"MemID"并总结"值"为"周"<= 2和<= 4(看看每个成员在第1-2周和第1-4周订购了多少.我目前的代码是:

MemberLTV <- memberorders %>%
group_by(MemID) %>%
summarize(
sum2 = sum(value[week<=2]),
sum4 = sum(value[week<=4]))

我现在正在尝试在汇总中添加另外两个字段,count2和count4,它们将计算每个条件的实例数(周<= 2且周<= 4).

所需的输出是:

output  = data.frame(MemID = c('A','B','C','D'),
                 sum2 = c(30,10,5,3),
                 sum4 = c(30,20,35,3),
                 count2 = c(2,1,1,1),
                 count4 = c(2,2,2,1))

我猜这只是sum函数的一个小调整,但是我很难搞清楚它.

Answer 1

尝试

 library(dplyr)
 memberorders %>% 
        group_by(MemID) %>% 
        summarise(sum2= sum(value[week<=2]), sum4= sum(value[week <=4]), 
                  count2=sum(week<=2), count4= sum(week<=4))

Answer 2

使用预览创意并保持一致:

MemberLTV_2 <- memberorders %>%

group_by(MemID) %>%
summarize(

    count2 = length(value[week<=2]),
    count4 = length(value[week<=4]),
    sum2 = sum(value[week<=2]),
    sum4 = sum(value[week<=4])

    )