merged data frame with <NA>
Hi Stefano, For the merge() part, I'll leave it to more expert users (I rarely use merge(), and every time I need it, it's painful...). To know why <NA> instead of NA, check the results with str(df3); I guess it is not the mode you expected. For more details, you should provide the file, or better a reproducible example using dput(). For the second part, your syntax was not correct (subsetting a column for elements based on a column that is not part of the subset!). And there is no column "pch" in your example. Try: df3[df3$event == "start", "event"] <- 24 HTH, Ivan -- Dr. Ivan Calandra TraCEr, laboratory for Traceology and Controlled Experiments MONREPOS Archaeological Research Centre and Museum for Human Behavioural Evolution Schloss Monrepos 56567 Neuwied, Germany +49 (0) 2631 9772-243 https://www.researchgate.net/profile/Ivan_Calandra
On 29/09/2020 9:59, Stefano Sofia wrote:
Dear R users,
I'm struggling with a simple "merge".
I have an external file called df.txt like
data_POSIX, event
2005-11-14 02:30:00, "start"
2005-11-14 11:30:00, "end"
I load it with
df1 <- read.table(file="df.txt", header=TRUE, sep=",", dec = ".", stringsAsFactors=FALSE)
df1$data_POSIX <- as.POSIXct(df1$data_POSIX, format="%Y-%m-%d %H:%M:%S", tz="Etc/GMT-1")
Then I create a new data frame df2:
day_1 <- as.POSIXct("2005-11-14-00-00", format="%Y-%m-%d-%H-%M", tz="Etc/GMT-1")
day_2 <- as.POSIXct("2005-11-14-12-00", format="%Y-%m-%d-%H-%M", tz="Etc/GMT-1")
df2 <- data.frame(data_POSIX=seq(day_1, day_2, by="30 min"))
Finally
df3 <- merge(df2, df1, by=c("data_POSIX"), all.x=TRUE)
gives
data_POSIX event
1 2005-11-14 00:00:00 <NA>
2 2005-11-14 00:30:00 <NA>
3 2005-11-14 01:00:00 <NA>
4 2005-11-14 01:30:00 <NA>
5 2005-11-14 02:00:00 <NA>
6 2005-11-14 02:30:00 start
7 2005-11-14 03:00:00 <NA>
8 2005-11-14 03:30:00 <NA>
9 2005-11-14 04:00:00 <NA>
10 2005-11-14 04:30:00 <NA>
11 2005-11-14 05:00:00 <NA>
12 2005-11-14 05:30:00 <NA>
13 2005-11-14 06:00:00 <NA>
14 2005-11-14 06:30:00 <NA>
15 2005-11-14 07:00:00 <NA>
16 2005-11-14 07:30:00 <NA>
17 2005-11-14 08:00:00 <NA>
18 2005-11-14 08:30:00 <NA>
19 2005-11-14 09:00:00 <NA>
20 2005-11-14 09:30:00 <NA>
21 2005-11-14 10:00:00 <NA>
22 2005-11-14 10:30:00 <NA>
23 2005-11-14 11:00:00 <NA>
24 2005-11-14 11:30:00 end
25 2005-11-14 12:00:00 <NA>
Why there is <NA> instead of NA?
And why
df3$pch[df3$event == "start"] <- 24
gives a whole column of NA and not 24 at row 6?
(oo)
--oOO--( )--OOo----------------
Stefano Sofia PhD
Civil Protection - Marche Region
Meteo Section
Snow Section
Via del Colle Ameno 5
60126 Torrette di Ancona, Ancona
Uff: 071 806 7743
E-mail: stefano.sofia at regione.marche.it
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