Skip to content
Prev 385813 / 398503 Next

merged data frame with <NA>

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
---Oo---------oO----------------

________________________________

AVVISO IMPORTANTE: Questo messaggio di posta elettronica pu? contenere informazioni confidenziali, pertanto ? destinato solo a persone autorizzate alla ricezione. I messaggi di posta elettronica per i client di Regione Marche possono contenere informazioni confidenziali e con privilegi legali. Se non si ? il destinatario specificato, non leggere, copiare, inoltrare o archiviare questo messaggio. Se si ? ricevuto questo messaggio per errore, inoltrarlo al mittente ed eliminarlo completamente dal sistema del proprio computer. Ai sensi dell?art. 6 della DGR n. 1394/2008 si segnala che, in caso di necessit? ed urgenza, la risposta al presente messaggio di posta elettronica pu? essere visionata da persone estranee al destinatario.
IMPORTANT NOTICE: This e-mail message is intended to be received only by persons entitled to receive the confidential information it may contain. E-mail messages to clients of Regione Marche may contain information that is confidential and legally privileged. Please do not read, copy, forward, or store this message unless you are an intended recipient of it. If you have received this message in error, please forward it to the sender and delete it completely from your computer system.

--
Questo messaggio  stato analizzato da Libra ESVA ed  risultato non infetto.
This message was scanned by Libra ESVA and is believed to be clean.