At the point where you say "date difference in days" IMO you have departed from
what `difftime` is for and are in the realm of a numeric measure. I ignore the
units inside `difftime` at all times and convert to numeric with a units
argument if I want to be that specific about how the measure is represented.
You may or may not recall the difference between angle ABC and the measure of
angle ABC (with a bar over it) from geometry... but the idea is the same...
distinguish the thing (time interval) from the numbers used to quantify it
(numeric).
elapsed_days <- function(end_date, start_date){
ed <- as.POSIXlt(end_date)
sd <- as.POSIXlt(start_date)
as.numeric( ed-sd, units="days" )
}
On May 22, 2019 2:43:42 PM PDT, reichm...@sbcglobal.net wrote:
>R Help
>
>I have a function to calculate a date difference in days but my results
>come
>back in hours. I suspect I am using the as.POSIXlt function
>incorrectly .
>
>Suggestions?
>
># Start time of data to be considered
>start_day <- "2016-04-30"
>
># Make event and sequence IDs into factors
>elapsed_days <- function(end_date, start_date){
> ed <- as.POSIXlt(end_date)
> sd <- as.POSIXlt(start_date)
> ed-sd
>}
>
>trans_sequence$eventID <- elapsed_days(trans_sequence$Date, start_day)
>
>
>> trans_sequence
># A tibble: 39 x 5
># Groups: Emitter [15]
> Emitter Date SIZE Geohash
>eventID
> <int> <date> <int> <chr>
><time>
> 1 1 2016-05-01 12 A;B;C;D;E;F;G;H;I;J;K;L
>19 hours
> 2 1 2016-05-02 5 A;B;C;D;E
>43 hours
> 3 1 2016-05-05 11 A;B;C;D;E;F;G;H;I;J;K
>115 hours
> 4 2 2016-05-01 9 C;D;E;F;G;H;I;J;K
>19 hours
> 5 2 2016-05-02 3 F;G;H
>43 hours
> 6 2 2016-05-05 3 L;M;N
>115 hours
> 7 3 2016-05-01 3 L;M;N
>19 hours
> 8 3 2016-05-02 3 I;J;K
>43 hours
> 9 3 2016-05-04 25
>A;B;C;D;E;F;G;H;I;J;K;L;M;N;O;P;Q;R;S;T;U;V;W;X;Y 91 hours
>10 3 2016-05-05 7 O;P;Q;R;S;T;U
>115 hours
>
>Jeff Reichman
>
>
> [[alternative HTML version deleted]]
>
>______________________________________________
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--
Sent from my phone. Please excuse my brevity.
______________________________________________
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