Hallo,
I have a table in which I would like to insert the min and max values of
another column (date and time in as.POSIXct Format).
This is my row table, where "su" and "sa" are still the same as "Vollzeit":
head(treat)
Vollzeit Datum Zugnacht su
sa
2 2013-09-09 20:15:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-09
20:15:00
3 2013-09-09 20:30:00 2013-09-09 2013-09-09 2013-09-09 20:30:00 2013-09-09
20:30:00
4 2013-09-09 20:45:00 2013-09-09 2013-09-09 2013-09-09 20:45:00 2013-09-09
20:45:00
5 2013-09-09 21:00:00 2013-09-09 2013-09-09 2013-09-09 21:00:00 2013-09-09
21:00:00
6 2013-09-09 21:15:00 2013-09-09 2013-09-09 2013-09-09 21:15:00 2013-09-09
21:15:00
7 2013-09-09 21:30:00 2013-09-09 2013-09-09 2013-09-09 21:30:00 2013-09-09
21:30:00
Now I want to insert the minimum value of "Vollzeit" for each date in
"Zugnacht" into the column "su" and the maximum value of "Vollzeit" for each
date in "Zugnacht" into the column "sa". If I do it like this, it does
exactly what I want:
zn <- unique(treat$Zugnacht)
i=zn[1]
treat$su[treat$Zugnacht==as.POSIXct(i, "UTC")] <-
min(treat$Vollzeit[treat$Zugnacht==as.POSIXct(i, "UTC")])
treat$sa[treat$Zugnacht==as.POSIXct(i, "UTC")] <-
max(treat$Vollzeit[treat$Zugnacht==as.POSIXct(i, "UTC")])
This is the result for the first date in "Zugnacht":
head(treat)
Vollzeit Datum Zugnacht su
sa
2 2013-09-09 20:15:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
3 2013-09-09 20:30:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
4 2013-09-09 20:45:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
5 2013-09-09 21:00:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
6 2013-09-09 21:15:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
7 2013-09-09 21:30:00 2013-09-09 2013-09-09 2013-09-09 20:15:00 2013-09-10
04:30:00
However I am not able to create a loop that runs over all 113 dates in zn. I
tried this, but it does not work. Can anybody help, please?
for (i in zn){
treat$su[treat$Zugnacht==as.POSIXct(zn[i], "UTC")] <-
min(treat$Vollzeit[treat$Zugnacht==as.POSIXct(zn[i], "UTC")])
treat$sa[treat$Zugnacht==as.POSIXct(zn[i], "UTC")] <-
max(treat$Vollzeit[treat$Zugnacht==as.POSIXct(zn[i], "UTC")])
}
Kind regards
Christiane
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