[R] Outputting a difftime object in PASTE or AS.CHARACTER is missing the unit + expand the format options?

[Rui Barradas]

Às 09:11 de 23/10/2024, Reuver, B de (epi) via R-help escreveu:
> Hello,
> 
> I was working on an R script using the datediff object, to log certain durations in the data processing.
> I ran in to the issue that outputing a datediff object using PASTE will leave out the time unit by default.
> 
> When you paste() or as.character() a datediff object it only outputs the numeric value, for example "1.23", so without the time unit secs, minutes, hours etc. This is arguably is not very useful, because 1.23 seconds is very different from 1.23 hours.
> 
> ```
> start_time <- Sys.time()
> result <- sum(1:10000)
> dur_time <- Sys.time() - start_time
> 
> print(paste(Sys.time(), "the process duration:", dur_time)) # "2024-10-23 09:57:10.69578 the process duration: 0.00280904769897461"
> 
> print(dur_time)               # "Time difference of 0.002809048 secs"
> print(paste(dur_time))        # "0.00280904769897461"
> print(as.character(dur_time)) # "0.00280904769897461"
> print(format(dur_time))       # "0.002809048 secs"
> 
> print(paste(dur_time, attr(dur_time, "units"))) # "0.00280904769897461 secs"
> ```
> 
> So my questions are:
> 1)  is it possible to have the default output for as.character for the datediff object also include the time unit? That way, it automatically outputs for example "1.23 seconds" when used in combination with paste().
> If someone really need just the numeric value without the unit, you can already use as.numeric(dur_time).
> 2) Is it possible to expand the format() options for the datediff object, so that it also accepts a strptime-like string, so like %H:%M:%S ? That way you have more output options without having to rely on third-party libraries
> 
> regards,
> Bas de reuver (UMCG, The Netherlands)
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Hello,

There are, in base R, methods

as.list.difftime
as.double.difftime

but not as.character.difftime.
If you write your own, it will be a functionality that only exists in 
your system and this can sometimes be a source for unexpected behavior.



as.character.difftime <- function(x) {
   u <- units(x)
   paste(unclass(x), u)
}

start_time <- Sys.time()
result <- sum(1:10000)
dur_time <- Sys.time() - start_time

as.character(dur_time)
#> [1] "0.000754117965698242 secs"


Hope this helps,

Rui Barradas


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