Convert Time Object to Categorical (Morning, Afternoon, Evening, Night) Variable in R

Label day timing into morning, afternoon and evening in R

You can achieve this with lubridate and cut.

library(lubridate)

# transform into date time column (if it is not already one)
df$Time_stamp <- ymd_hms(df$Time_stamp)

# create breaks
breaks <- hour(hm("00:00", "6:00", "12:00", "18:00", "23:59"))
# labels for the breaks
labels <- c("Night", "Morning", "Afternoon", "Evening")

df$Time_of_day <- cut(x=hour(df$Time_stamp), breaks = breaks, labels = labels, include.lowest=TRUE)

df

        Id          Time_stamp Time_of_day
1 3083188c 2016-08-29 13:10:51   Afternoon
2 924d500e 2016-08-29 09:22:33     Morning
3 ad4dd7ff 2016-08-25 20:29:35     Evening

data:

df <- structure(list(Id = c("3083188c", "924d500e", "ad4dd7ff"), 
                     Time_stamp = c("2016-08-29 13:10:51", "2016-08-29 09:22:33", "2016-08-25 20:29:35")), 
                .Names = c("Id","Time_stamp"),
                class = "data.frame", 
                row.names = c(NA, -3L))

Grouping of data with certain criteria

Convert VisitTime to POSIXct format, extract hour from it, define "Morning", "Afternoon", "Evening" and "Night" and assign labels.

library(dplyr)

df %>%
  mutate(time = as.POSIXct(VisitTime, format = "%H:%M"), 
         hour = as.integer(format(time, '%H')), 
         Label  = case_when(between(hour, 6, 11) ~ "Morning", 
                            between(hour, 12, 15) ~"Afternoon", 
                            between(hour, 16, 19) ~"Evening", 
                            TRUE ~"Night"))

How to separate data into morning and afternoon

First split:

library(dplyr)

DQ <- 
  DQ |>
  mutate(morning = format(as.POSIXct(Start.time, format = "%m-%d-%y %H:%M:%S"), "%H") < 12) |>
  group_by(morning) |>
  group_split()

Output:

[[1]]
# A tibble: 2 × 6
     ID Date       Start.time       Completion.time  Email     morning
  <int> <chr>      <chr>            <chr>            <chr>     <lgl>  
1     4 2022-02-28 2-28-22 23:19:36 2-28-22 23:21:52 anonymous FALSE  
2     6 2022-03-01 3-1-22 21:04:49  3-1-22 21:06:31  anonymous FALSE  

[[2]]
# A tibble: 4 × 6
     ID Date       Start.time       Completion.time  Email     morning
  <int> <chr>      <chr>            <chr>            <chr>     <lgl>  
1     1 2022-02-15 2-15-22 11:15:43 2-15-22 11:16:59 anonymous TRUE   
2     2 2022-02-25 2-25-22 8:52:33  2-25-22 8:55:02  anonymous TRUE   
3     3 2022-02-25 2-25-22 8:55:08  2-25-22 16:16:37 anonymous TRUE   
4     5 2022-03-01 3-1-22 8:58:31   3-1-22 9:00:02   anonymous TRUE   

Then save:

library(readr)

write_csv(DQ[[1]], "afternoon.csv")
write_csv(DQ[[2]], "morning.csv")

Get part of day (morning, afternoon, evening, night) in Python dataframe

Use cut or custom function with and and also changed < to > and > to <= and also for each value add return:

prods = pd.DataFrame({'hour':range(1, 25)})

b = [0,4,8,12,16,20,24]
l = ['Late Night', 'Early Morning','Morning','Noon','Eve','Night']
prods['session'] = pd.cut(prods['hour'], bins=b, labels=l, include_lowest=True)

---

def f(x):
    if (x > 4) and (x <= 8):
        return 'Early Morning'
    elif (x > 8) and (x <= 12 ):
        return 'Morning'
    elif (x > 12) and (x <= 16):
        return'Noon'
    elif (x > 16) and (x <= 20) :
        return 'Eve'
    elif (x > 20) and (x <= 24):
        return'Night'
    elif (x <= 4):
        return'Late Night'

---

prods['session1'] = prods['hour'].apply(f)
print (prods)
    hour        session       session1
0      1     Late Night     Late Night
1      2     Late Night     Late Night
2      3     Late Night     Late Night
3      4     Late Night     Late Night
4      5  Early Morning  Early Morning
5      6  Early Morning  Early Morning
6      7  Early Morning  Early Morning
7      8  Early Morning  Early Morning
8      9        Morning        Morning
9     10        Morning        Morning
10    11        Morning        Morning
11    12        Morning        Morning
12    13           Noon           Noon
13    14           Noon           Noon
14    15           Noon           Noon
15    16           Noon           Noon
16    17            Eve            Eve
17    18            Eve            Eve
18    19            Eve            Eve
19    20            Eve            Eve
20    21          Night          Night
21    22          Night          Night
22    23          Night          Night
23    24          Night          Night

How to create a day/night factor from POSIXct variable

Data

library(data.table)

SightingTime_chr = c("2017-07-31 09:56:27 UTC", "2017-07-31 10:36:30 UTC", "2017-08-01 00:07:20 UTC","2017-08-01 01:31:00 UTC", "2017-08-01 10:38:23 UTC", "2017-08-01 21:13:06 UTC", "2017-08-02 15:13:30 UTC", "2017-08-02 18:05:28 UTC", "2017-08-02 21:04:08 UTC")
x = data.table(SightingTime_chr)

Code

A couple of things were not quite right with your conversion to datetime (the format for example):

x$SightingTime = as.POSIXct(x$SightingTime_chr, format = "%Y-%m-%d %H:%M:%S", tz = "UTC")
attributes(x$SightingTime)$tzone <- "America/Halifax"

I would first convert the character strings to POSIXct and then convert to the America/Halifax timezone as the original vector seems to be in UTC datetime (omit the second step if I#m wrong).

x$TOD <- format(x$SightingTime, format="%H%M%S")

x$daynight = with(x, ifelse(TOD > "053000" & TOD < "200000", "Day", "Night")) 

I convert the time of day to a pseudo-numeric value (the values are not technically correct but this should be enough for the comparison purpose).

x$daynight
[1] "Day"   "Day"   "Night" "Night" "Day"   "Day"   "Day"   "Day"   "Day" 

Now the results appear correct.

Alternative

From this answer we can get an elegant solution in case we want mor than just night/day:

nightday <- function(datetime) {
  paste(
    c("Night", "Morning", "Afternoon", "Evening", "Night")[
      cut(as.numeric(format(datetime, "%H%M")), c(0, 530, 1100, 1700 ,2000, 2359))
      ]
  )
}
nightday(x$SightingTime)
[1] "Morning"   "Morning"   "Night"     "Night"     "Morning"   "Evening"   "Afternoon" "Afternoon" "Evening"  

Cut day into multiple parts

Turn timestamp to the POSIXlt object and extract hour of time by the $ symbol.

da$daypart <- as.POSIXlt(da$timestamp)$hour + 1

#                 timestamp daypart
# 1 2016-01-24 01:17:37 GMT       2
# 2 2016-01-24 02:09:41 GMT       3
# 3 2016-01-24 13:34:35 GMT      14
# 4 2016-01-24 15:17:56 GMT      16
# 5 2016-01-24 18:14:55 GMT      19

---

Edit: Split time into 48 parts

time <- as.POSIXlt(da$timestamp)
da$daypart48 <- time$hour * 2 + (time$min > 30) + 1
da

#                 timestamp daypart daypart48
# 1 2016-01-24 01:17:37 GMT       2         3
# 2 2016-01-24 02:09:41 GMT       3         5
# 3 2016-01-24 13:34:35 GMT      14        28
# 4 2016-01-24 15:17:56 GMT      16        31
# 5 2016-01-24 18:14:55 GMT      19        37

Displaying morning, afternoon, or evening to user based on time using variables

If you are linking the javascript file before the span, then
Uncaught TypeError: Cannot set property 'innerHTML' of null at master.js:13 will occur since it can't find the span yet. Try:

window.onload = function(e){ 
    document.getElementById("time").innerHTML = time;
}

---

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