目标:
我有一个数据集df,我希望首先统计每个日期的出现次数,然后将输出乘以一定的数目。
Sent Duration Length
1/7/2020 8:11:00 PM 34 216
1/22/2020 7:51:05 AM 432 111
1/7/2020 1:35:08 AM 57 90
1/22/2020 3:43:26 AM 22 212
1/22/2020 4:00:00 AM 55 500
预期结果:
Date Count Aggregation(80)
1/7/2020 2 160
1/22/2020 3 240
我希望计算特定'datetime'发生的次数,然后将该结果乘以80。日期1/7/2020发生两次,日期1/22/2020发生3次。然后,我将此数字乘以数字80。
目标是:
structure(list(Sent = structure(c(5L, 3L, 4L, 1L, 2L), .Label = c("1/22/2020 3:43:26 AM",
"1/22/2020 4:00:00 AM", "1/22/2020 7:51:05 PM", "1/7/2020 1:35:08 AM",
"1/7/2020 8:11:00 PM"), class = "factor"), Duration = c(34L,
432L, 57L, 22L, 55L), length = c(216L, 111L, 90L, 212L, 500L)), class = "data.frame", row.names = c(NA,
-5L))
这是我尝试过的:
df1<- aggregate(df$Sent, by=list(Category= df$dSent),
FUN=length)
但是,我需要输出日期与汇总一起出现的频率(乘以80)
欢迎提出任何建议。
这里是data.table
的方式。代码
library( data.table )
#set data as data.table
setDT(mydata)
#set timestamps as posix
mydata[, Sent := as.POSIXct( Sent, format = "%m/%d/%Y %H:%M:%S %p" ) ]
#summarise
mydata[, .(Count = .N, Aggregation = .N * 80), by = .(Date = as.Date(Sent) )]
输出
# Date Count Aggregation
# 1: 2020-01-07 2 160
# 2: 2020-01-22 3 240