Hello Gentlemen, All of your answers were helpfull. Indeed, 'as.is=TRUE' or 'stringsAsFactors=FALSE' avoid importing as factors, as it did when I imported the table without specifying anything. However, data frames will not allow different datatypes within a single column, so, for time series, I should work with a transpose of the table. However, when the time series is the label of a profile, I should read the table with 'header = TRUE'.
In other words: * Plotting values of a column (let's say againts observation number) for a selected time (where time is the name of the series): import data with 'header = TRUE' * Plotting the evolution of the values for a single observation number against time: 'header = TRUE' & transpose & 'as.is=TRUE' Kind Regards, Serge-Étienne Parent Golder Associés Canada separent wrote: > > #Hello, > > #I loaded data using read.table - I needed to convert a row in the data > frame to date class: > >> data > > V1 V2 V3 V4 > 1 2008-05-19 2008-04-19 2008-03-21 2008-02-22 > 2 38.16999817 30.70999908 36.86000061 35.18999863 > 3 37.47999954 29.95000076 36.45999908 35.36000061 > 4 37.47999954 30.14999962 36.47000122 35.36000061 > 5 37.84999847 30.56999969 36.84000015 35.74000168 > 6 38.38999939 31.14999962 37.34000015 36.27000046 > 7 39.11000061 31.90999985 38.02999878 36.97999954 > 8 39.81000137 32.65000153 38.68000031 37.63999939 > 9 40.47000122 33.34999847 39.27999878 38.27000046 > >> data[1,] > V1 V2 V3 V4 > 1 2008-05-19 2008-04-19 2008-03-21 2008-02-22 > >> dates1<-as.Date(data[1,]) > > do not know how to convert 'dates[1,]' to class "Date" > > # However, I can individually convert them all: > >> dates1.1<-as.Date(data[1,1]) > >> dates1.1 > [1] "2008-05-19" > > # How can I change the class of the date over the entire row (my original > file contains more than one hundred rows)? > # Thank you very much. > -- View this message in context: http://old.nabble.com/as.Date-from-data.frame-tp26305830p26307735.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
