[R] How do I "teach" R that columns 1, 2, and 3 are the Year-Month-Day

[Martin Maechler]

>>>>> Ebert,Timothy Aaron 
>>>>>     on Wed, 15 Jun 2022 02:01:44 +0000 writes:

    > You don't, or not exactly. You could make the three
    > columns strings, then add them together. I would then use
    > the lubridate package to convert to a date.  The first
    > four lines of code are just getting a bit of data into
    > R. The lubridate package will also work with date-time
    > objects if you have time.

    > year<-rep("2021",4) 
    > month<-c(7,8,9,11)
    > day<-c(25,27,26,4)
    > fuel<-c(50.45, 61.48,59.07,55.40)
    > df<-data.frame(year,month,day,fuel)
    > df$day <-as.character(df$day)
    > df$month<-as.character(df$month)
    > df$date <- paste(year,"/",month,"/",day)
    > library(lubridate)
    > df$date<-ymd(df$date)

    > Regards,
    > Tim

Thank you, but
Jeff Newmiller's answer which was much shorter *and* only
used base R  instead of an extra package was much more convincing to me.

Martin

    > -----Original Message-----
    > From: R-help <r-help-bounces using r-project.org> On Behalf Of Avi Gross via R-help
    > Sent: Tuesday, June 14, 2022 10:00 PM
    > To: r-help using r-project.org
    > Cc: r-help using r-project.org
    > Subject: Re: [R] How do I "teach" R that columns 1, 2, and 3 are the Year-Month-Day

    > [External Email]

    > Greg,
    > It looks like you mean to have a data.frame containing the year as a column then Month, Day and something called Fuel.
    > You only made a vector called Fuel, with no name as part of it and plotted it.
    > So you did not expect any names, I assume.
    > You probably want to combine the first three columns into holding some kind of date object with something like as.Date("2021-07-25") for each row and make a vector of those. Your data.frame might then contain two columns called Date and Fuel and you might use whatever plotting method to put Fuel on the Y axis and dates on the X axis or whatever makes sense. Plotting four independent columns will not work here.
    > And note the NAMES go in with something like:
    > mydata <- data.frame(Date=dates, Fuel=Fuel) I have not done all the work but hopefully this is helpful.

    > -----Original Message-----
    > From: Gregory Coats via R-help <r-help using r-project.org>
    > To: Greg Comcast Coats <gregcoats using me.com>
    > Cc: Marc Schwartz via R-help <r-help using r-project.org>
    > Sent: Tue, Jun 14, 2022 9:08 pm
    > Subject: [R] How do I "teach" R that columns 1, 2, and 3 are the Year-Month-Day

    > # Column 1 is the Year
    > # Column 2 is the Month
    > # Column 3 is the Day
    > # Column 4 is the Fuel
    > Fuel <- c(50.45, 61.48, 59.07, 55.40, 30.63, 41.35, 32.81, 49.86, 62.99, 89.37) plot (Fuel)

    > 2021  7 25  50.45
    > 2021  8 27  61.48
    > 2021  9 26  59.07
    > 2021 11  4  55.40
    > 2021 11 22  30.63
    > 2021 11 26  41.35
    > 2021 12  6  32.81
    > 2022  1 14  49.86
    > 2022  4 29  62.99
    > 2022  6 11  89.37

    > How do I "teach" R that columns 1, 2, and 3 are the Year-Month-Day?
    > Greg Coats
    > [[alternative HTML version deleted]]

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