[英]Average Time Difference Between Two Dates PER Group
I have a dataframe with users and their visit dates.我有一个包含用户及其访问日期的数据框。 I'm trying to find the average time difference between visits per group.我试图找出每组访问之间的平均时间差。 The output would be in days or fraction of a day输出将以天或一天的一小部分为单位
require(lubridate)
so <- data.frame(visit_dates = c("12/4/2016","12/6/2016","12/7/2016","12/3/2016","12/7/2016","12/10/2016"), person = c("1","1","1","2","2","2"))
so$visit_dates <- mdy(format(as.POSIXct(strptime(so$visit_dates,"%m/%d/%Y",tz = "")),format = "%m/%d/%Y"))
The output would look something like:输出将类似于:
person avgTimeBetweenVisit
1 2.5
2 3.5
What about that:那个怎么样:
so %>%
group_by(person)%>%
mutate(Difference = visit_dates - lag(visit_dates)) %>%
summarize(mean_time = mean(Difference, na.rm=TRUE))
That link helped me with the 'diff' problem.该链接帮助我解决了“差异”问题。 diff operation within a group, after a dplyr::group_by() 组内的差异操作,在 dplyr::group_by() 之后
Try data.table:试试数据表:
require(lubridate)
require(data.table)
so <- data.frame(visit_dates = c("12/4/2016","12/6/2016","12/7/2016","12/3/2016","12/7/2016","12/10/2016"), person = c("1","1","1","2","2","2"))
so$visit_dates <- mdy(format(as.POSIXct(strptime(so$visit_dates,"%m/%d/%Y",tz = "")),format = "%m/%d/%Y"))
so <- data.table(so, key = c("person", "visit_dates"))
res <- so[, .(avgTimeBetweenVisit = mean(diff(visit_dates))), by = person]
print(res)
# person avgTimeBetweenVisit
# 1: 1 1.5 days
# 2: 2 3.5 days
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