Obtain Time format from a String - r

I am getting Data where the first column is always a string with the Time like
Time <- "2015-06-01 09:45:33"
for plotting, later I convert it with as.POSIXct and so on.
But sometimes I have another Time string like
Time <- "2015/07/01 09:33"
So is there a possibility(or a function) to check the Time format of the string in a way like this
format <- checkFormat(Time)
and then convert it automatically to
as.POSIXct(Time, format=format)
I cant be the first one who asks this, although i really searched a lot.
Thanks

As requested in answer format: it is not possible, since in your example no solution can know if 06 is the month and 01 the day or vice versa.

You can change the time format string with
Time <- "2015/07/01 09:33"
Time <- if(grepl("\\d{4}/\\d{2}/\\d{2}", Time)) gsub("/", "-", Time)

Related

how I can convert an specific character string to date time in r?

Hi and thanks for reading me. Im trying to convert a character string in to a datetime format in r, but I cannot discover the way to do that, because the year is only taken the last 2 digits ("22" instead of "2022"), im not sure of how to fix It.
The character string is "23/8/22 12:45" and I tried with:
as.Date("23/8/22 12:45", format ="%m/%d/%Y" )
and
as_datetime(ymd_hm("23/8/22 12:45"), format ="%m/%d/%Y")
But it doest work. Anyone knows how I can fix it? thanks for the help
as.Date returns only the calendar date, because class Date objects are only shown as calendar dates.
in addition to POSIXct, you can also use parse_date_time from lubridate package:
library(lubridate)
parse_date_time("23/8/22 12:45", "dmy HM", tz="") #dmy - day, month, year HM - hour, minute
# Or the second function:
dmy_hm("23/8/22 12:45",tz=Sys.timezone())
As has been mentioned in the comments you need to use "%d/%m/%y" to correctly parse the date in your string. But, if you want datetime format (in base r this is normally done with POSIXct classes) you could use as.POSIXct("23/8/22 12:45", format = "%d/%m/%y %H:%M"). This will make sure you keep information about the time from your string.

Lubridate or ANYTIME to convert from 24hr to 12hr time

As the title suggests, I am trying to use either lubridate or ANYTIME (or similar) to convert a time from 24 hour into 12 hour.. To make life easier I don't need the whole time converted.
What I mean is I have a column of dates in this format:
2021-02-15 16:30:33
I can use inbound$Hour <- hour(inbound$Timestamp) to grab just the hour from the Timestamp which is great.. except that it is still in 24hr time. (this creates an integer column for the hour number)
I have tried several mutates such as inbound <- inbound %>% mutate(Hour = ifelse(Hour > 12, sum(Hour - 12),Hour)
This technically works.. but I get some really wonky values (I get a -294 in several rows for example)..
is there an easier way to get the 12hr time converted?
Per recommendation below I tried to use a base FORMAT as follows:
inbound$Time <- format(inbound$Timestamp, "%H:%M:%S")
inbound$Time <- format(inbound$Time, "%I:%M:%S")
and on the second format I am getting an error
Error in format.default(inbound$Time, "%I:%M:%S") :
invalid 'trim' argument
I did notice the first format converts to a class CHARACTER column.. not sure if that is causing issues with the 2nd format or not..
I then also tried:
`inbound$time <- format(strptime(inbound$Timestamp, "%H:%M:%S"), "%I:%M %p")`
Which runs without error.. but it creates a full column of NA's
Final edit::::: I made the mistake of mis-reading/applying the solution and that caused errors.. when using the inbound$Time <- format(inbound$Time, "%I:%M:%S") or as.numeric(format(inbound$Timestamp, "%I")) from the comments... both worked and solved the issue I was having.
To be clear... From 2021-02-15 16:30:33 you want just 04:30:33 as a result?
No need for lubridate or anytime. Assuming that is a Posixct
a <- as.POSIXct("2021-02-15 16:30:33")
a
# [1] "2021-02-15 16:30:33 UTC"
b <- format(a, "%H:%M:%S")
b
#[1] "16:30:33"
c <- format(a, "%I:%M:%S")
c
#[1] "04:30:33"

format - display fractional time data as hh:mm:ss R

I have data below for work hours which I need to compare - start and stop with date and time. I first extract the time portion of each as start and stop variables, then use the chron package to change them from factor data to something I can compare more easily.
require(chron)
eg_data3 <- data.frame(
id = c('42', '42', '42', '42', '42'),
time_in = as.factor(c('11/5/2017 13:52', '11/4/2017 14:25', '11/5/2017 15:30', '11/5/2017 17:10', '11/6/2017 18:20')),
time_out = as.factor(c('11/5/2017 13:59', '11/4/2017 14:59', '11/5/2017 16:00', '11/5/2017 17:45', '11/6/2017 18:50')))
eg_data3$start_time <- substring(strptime(eg_data3$time_in, format = "%m/%d/%Y %H:%M"),12,19)
eg_data3$end_time <- substring(strptime(eg_data3$time_out, format = "%m/%d/%Y %H:%M"),12,19)
eg_data3$end_time <- chron(times = eg_data3$end_time)
eg_data3$start_time <- chron(times = eg_data3$start_time)
Next, I generate another variable which compares the difference between stop time 1, and start time 2, IE stop time in row 1 with start time in row 2, to see the gap between them.
require(dplyr)
eg_data3 <- eg_data3 %>% group_by(id) %>% mutate(diff_outX0_inX1 = start_time - lag(end_time))
When I do this, the variable is formatted as a decimal. I cannot for the life of me get it to display as hh:mm:ss. I have tried specifying out.format as hh:mm:ss in chron, changing time_in / time_out to numeric and character before and after extraction and applying chron(times), changing the format of the diff_ variable after, etc.
What seems like a very simple question -
How do I get the result comparison (diff_outX0_inX1) variable to display as time, either hh:mm or hh:mm:ss ?? I know the formula to convert fractional days into minutes in Excel, but I'd prefer to not write out a two step function, I assume it's a simple formatting issue.
Any help is appreciated.
EDIT - got flagged as a duplicate...OK. I asked if there was a way to do this that did not involve writing a function. The answer that was linked involves a function. First comment provided a clean simple answer. I can reproduce the answer in the comment, I could not reproduce the function myself, not nearly as helpful. I also added another solution that does not requre dplyr. No where I looked online showed me something as simple as "just format the result with chron."

Converting a numeric value to time in R [duplicate]

I have a data frame containing what should be a datetime column that has been read into R. The time values are appearing as numeric time as seen in the below data example. I would like to convert these into datetime POSIXct or POSIXlt format, so that date and time can be viewed.
tdat <- c(974424L, 974430L, 974436L, 974442L, 974448L, 974454L, 974460L, 974466L, 974472L,
974478L, 974484L, 974490L, 974496L, 974502L, 974508L, 974514L, 974520L, 974526L,
974532L,974538L)
974424 should equate to 00:00:00 01/03/2011, but the do not know the origin time of the numeric values (i.e. 1970-01-01 used below does not work). I have tried using commands such as the below to achieve this and have spent time trying to get as.POXISct to work, but I haven’t found a solution (i.e. I either end up with a POSIXct object of NAs or end up with obscure datetime values).
Attempts to convert numeric time to datetime:
datetime <- as.POSIXct(strptime(time, format = "%d/%m/%Y %H:%M:%S"))
datetime <- as.POSIXct(as.numeric(time), origin='1970-01-01')
I am sure that this is a simple thing to do. Any help would be greatly received. Thanks!
Try one of these depending on which time zone you want:
t.gmt <- as.POSIXct(3600 * (tdat - 974424), origin = '2011-03-01', tz = "GMT")
t.local <- as.POSIXct(format(t.gmt))

Extract dates times from a data.frame in R

I have a dataset with some date time like this "{datetime:2015-07-01 09:10:00" So I wanted to remove the text, and then keep the date & the time as as.Date returns only the date. So I write this code but the only problem I have is that during the second line with strsplit, it only returns me the date time of the first line and so erase the others... I woud love to get ALL my date time not only the first. I thought about sapply maybe, but I can't make it right I have many errors or maybe with a loop for? I am novice to R so I don't really know how to do this the best way.
Could you help me please? Besides If you have another idea for the time & date format or a simple way to do it, it should be very nice of you too.
data$`Date Time`=as.character(data$`Date Time`)
data$`Date Time`=unlist(strsplit(data[,1], split='e:'))[2]
date=substr(data$`Date Time`,0,10)
date=as.Date(date)
time=substr(data$`Date Time`,12,19)
data$Date=date
data$Time=time
Thank you very much for your help!
You could use the format argument to avoid all the strsplit:
times <- as.POSIXct(data$`Date Time`, format='{datetime:%Y-%m-%d %H:%M:%S')
(The reason for the "{datetime:" in the format is because you mentioned this is the format of your strings).
This object has both date and time in it, and then you can just store it in the dataframe as a single column of type POSIXct rather than two columns of type string e.g.
data$datetime <- times
but if you do want to store the date as a Date and the time as a string (as in your example above):
data$Date <- as.Date(times)
data$Time <- strftime(times, format='%H:%M:%S')
See ?as.Date, ?as.POSIXct, ?strptime for more details on that format argument and various conversions between date and string.

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