几个日期之间的时间间隔（天和小时）

Question

I know a lot of questions have been asked on the same subject but I have not found an answer to this particular question, despite trying to adapt other codes to my problem.

My data frame "v1" has more than 300 thousand lines with the variable "Date" in the following format:

Date
2015-07-27 17:35:00
2015-07-27 17:40:00
2015-07-27 17:45:00

1st I want to know if all the "Date" intervals are in the 5 to 5 minutes interval. If not I would like to track where different intervals are.

2nd I pretend to create a new column where it can be seen the time stamp of the different intervals. For example, "time_int" where it would be seen "00:05:00", "00:05:00"...

Any help will be appreciated. Thank you in advance.

Answer 1

You can use rollapplyr to find the time difference between two consecutive rows. And then you can use which to find the rows that the time difference is not 5 minutes.

dt=read.table(text=text, header=TRUE)
library(lubridate)
library(dplyr)
library(zoo)
dt=mutate(dt, Date=ymd_hms(Date)) %>%
  mutate(dt, Dif=rollapplyr(Date, 2, function(x) {
  return(difftime(x[2], x[1]))
}, fill=NA))
dt
                 Date Dif
1 2015-07-27 17:35:00  NA
2 2015-07-27 17:40:00   5
3 2015-07-27 17:45:00   5
4 2015-07-27 17:49:00   4

dt[which(dt$Dif != as.difftime(5, units="mins")),]
                 Date Dif
4 2015-07-27 17:49:00   4

Lastly, to format the times in your desired format:

dt %>% mutate(DifString=format(.POSIXct(Dif*60, tz="GMT"), "%H:%M:%S"))
                 Date Dif DifString
1 2015-07-27 17:35:00  NA      <NA>
2 2015-07-27 17:40:00   5  00:05:00
3 2015-07-27 17:45:00   5  00:05:00
4 2015-07-27 17:49:00   4  00:04:00

Data

text="Date
'2015-07-27 17:35:00'
'2015-07-27 17:40:00'
'2015-07-27 17:45:00'
'2015-07-27 17:49:00'"
dt=read.table(text=text, header=TRUE)

Answer 2

Here is an option to calculate the difference using lag . If you'd like, you could create another column showing hours with units = "hours" .

library(tidyverse)
library(lubridate)


df <- data.frame(date = ymd_hms(c("2015-07-27 17:35:00", 
"2015-07-27 17:40:00", "2015-07-27 17:49:00", "2015-07-27 19:49:00")))

df %>% 
  mutate(diff = date - lag(date),
         diff_minutes = as.numeric(diff, units = "mins"),
         time_int = format(.POSIXct(diff_minutes*60, "UTC"), "%H:%M:%S")) %>% 
  select(date, diff_minutes, time_int) %>% 
  # Filter the data for a range of minutes
  filter(diff_minutes >= 5 & diff_minutes < 10)

# OUTPUT:

#>                  date diff_minutes time_int
#> 1 2015-07-27 17:40:00            5 00:05:00
#> 2 2015-07-27 17:49:00            9 00:09:00

^{Created on 2021-03-09 by the reprex package (v0.3.0)}

Original Data

date
<S3: POSIXct>
2015-07-27 17:35:00             
2015-07-27 17:40:00             
2015-07-27 17:49:00             
2015-07-27 19:49:00