R 按列值获取计数
我有一个如下所示的数据帧:R 按列值获取计数,r,R,我有一个如下所示的数据帧: month create_time request_id weekday 1 4 2014-04-25 3647895 Friday 2 12 2013-12-06 2229374 Friday 3 4 2014-04-18 3568796 Friday 4 4 2014-04-18 3564933 Friday 5 3 2014-03-07 3081503 Friday 6
month create_time request_id weekday
1 4 2014-04-25 3647895 Friday
2 12 2013-12-06 2229374 Friday
3 4 2014-04-18 3568796 Friday
4 4 2014-04-18 3564933 Friday
5 3 2014-03-07 3081503 Friday
6 4 2014-04-18 3568889 Friday
我想在工作日获得请求ID的计数。我在R怎么做
我已经尝试了很多基于ddply和aggregate的东西,但运气不佳。尝试使用
aggregate
> aggregate(request_id ~ weekday, FUN=length, dat=df)
weekday request_id
1 Friday 6
尝试使用
aggregate
> aggregate(request_id ~ weekday, FUN=length, dat=df)
weekday request_id
1 Friday 6
有几种有效的方法可以做到这一点。我通常使用可靠的
sqldf()
。如果数据帧名为D,则
library(sqldf)
counts <- sqldf('select weekday, count(request_id) as nrequests from D group by weekday')
库(sqldf)
计数有几种有效的方法。我通常使用可靠的sqldf()
。如果数据帧名为D,则
library(sqldf)
counts <- sqldf('select weekday, count(request_id) as nrequests from D group by weekday')
库(sqldf)
计数或。。。你可以试试:
count(df,"weekday")
或
或者。。。你可以试试:
count(df,"weekday")
或
另一个选项是使用表
并获取行和
> rowSums(with(dat, table(weekday, request_id)))
Friday
6
另一个选项是使用表
并获取行和
> rowSums(with(dat, table(weekday, request_id)))
Friday
6