How to add 05:30 to Time column?

Question

In my data frame I want to add 5hrs and 30minutes to the Time column and then group the Time field into 2 hours(0-2,3-6.. like this till 21-23). Here is the data frame below:

Time      Date          Device
7:12:20   12/14/2016    Tablet
8:57:34   12/12/2016    Desktop
18:48:36  12/1/2016     Desktop
4:27:34   12/16/2016    Desktop
5:57:48   12/28/2016    Desktop
10:28:31  12/20/2016    Desktop
10:28:32  12/20/2016    Desktop

Answer 1

This would be one way to handle your case. Your data is called mydf here. First, you can create a date object using paste() and as.POSIXct(). Since you want to add 2 hours and 30 minutes, I added 60 (sec) * 150 (min) to the date object and created foo. Then, I extracted the hour-minute-second part from foo and created a new column called Time2. The last job is to create a group variable with cut(). I do not know how you want to label the groups, so I named them as group 1, group 2, and so on.

library(dplyr)

mydf %>%
mutate(foo = as.POSIXct(paste(Date, Time, sep = " "),
                format("%m/%d/%Y %H:%M:%S"), tz = "UTC") +
                (60 * 150),
       Time2 = format(foo, "%H:%M:%S"),
       group = cut(as.numeric(format(foo, "%H")), breaks = seq(0, 24, 3),
                   labels = paste("group", 1:8, sep = " "),
                   include.lowest = TRUE)) %>%
select(-foo)

#      Time       Date  Device    Time2    group
#1  7:12:20 12/14/2016  Tablet 09:42:20  group 3
#2  8:57:34 12/12/2016 Desktop 11:27:34  group 4
#3 18:48:36  12/1/2016 Desktop 21:18:36  group 7
#4  4:27:34 12/16/2016 Desktop 06:57:34  group 2
#5  5:57:48 12/28/2016 Desktop 08:27:48  group 3
#6 10:28:31 12/20/2016 Desktop 12:58:31  group 4
#7 10:28:32 12/20/2016 Desktop 12:58:32  group 4

DATA

mydf <- structure(list(Time = c("7:12:20", "8:57:34", "18:48:36", "4:27:34", 
"5:57:48", "10:28:31", "10:28:32"), Date = c("12/14/2016", "12/12/2016", 
"12/1/2016", "12/16/2016", "12/28/2016", "12/20/2016", "12/20/2016"
), Device = c("Tablet", "Desktop", "Desktop", "Desktop", "Desktop", 
"Desktop", "Desktop")), .Names = c("Time", "Date", "Device"), class = "data.frame", row.names = c(NA, 
-7L))

Answer 2

There are multiple ways of doing it.

Case 1 : Converting 5 hrs and 30 minutes into the seconds and adding it to the time column.

*I must prefer before adding the time i.e 5hrs and 30 minutes you must merge the time and date columns in case you have time nearby 2100 hrs result in the change of date *

once you have join the columns you proceed with the following:

dataframe$newtime <- as.POSIXct(dataframe$dateandtimetogether) + noofseconds

Case 2 : By defining functions for hrs and mins

In this case to you must join the date and time column, later it can be separated easily

hrs <- function(u) {
  x <- u * 3600
return(x)
}

mns <- function(m) {
  x <- m * 60
  return(x)
}


dataframe$newtime <- as.POSIXct(dataframe$dateandtimetogether)  + hrs(5) + mns(30)

Answer 3

Something like:

hms("20:00:00") + hm("5:30")

is going to produce an object holding:

## [1] "25H 30M 0S"

Not exactly useful (in this context).

Here's a way to add the time and create the breaks:

df <- read.table(text="Time      Date          Device
7:12:20   12/14/2016    Tablet
8:57:34   12/12/2016    Desktop
18:48:36  12/1/2016     Desktop
4:27:34   12/16/2016    Desktop
5:57:48   12/28/2016    Desktop
10:28:31  12/20/2016    Desktop
10:28:32  12/20/2016    Desktop", header=TRUE, stringsAsFactors=FALSE)

library(lubridate)
library(magrittr)

(mdy_hms(sprintf("%s %s", df$Date, df$Time)) + hm("5:30")) %>%
  hour() %>%
  cut(breaks=seq(0, 24, 2), include.lowest=TRUE)
## [1] (10,12] (12,14] [0,2]   (8,10]  (10,12] (14,16] (14,16]
## 12 Levels: [0,2] (2,4] (4,6] (6,8] (8,10] (10,12] (12,14] ... (22,24]