When read.table imports a table that includes a header called 'Date', it tries to recognize the date format. For example, if one imports this data from Yahoo finance, the Date column is automatically transformed to Y-m-d, whereis in the data it appears as m/d/Y: myData <- read.csv("http://ichart.finance.yahoo.com/table.csv?s=GOOG&a=07&b=19&c=2004&d=03&e=16&f=2010&g=d&ignore=.csv") However, it does not actually convert the variable to Date format. MyData$Date is still a factor. This combination of converting the format but not attributing the 'Date' class is for me extremely unfortunate behavior. My scripts still don't recognize the variable as being a date, but it also becomes harder to manually convert it using as.Date() because it is no longer in the original format. Is there a way to either automatically convert to as.Date() when a date format has been detected, or otherwise disable this transformation at all? -- View this message in context: http://n4.nabble.com/read-table-behavior-for-Dates-tp2013442p2013442.html Sent from the R help mailing list archive at Nabble.com.
use the argument colClasses of read.table Kjetil On Fri, Apr 16, 2010 at 3:32 PM, Jeroen Ooms <jeroenooms at gmail.com> wrote:> > When read.table imports a table that includes a header called 'Date', it > tries to recognize the date format. For example, if one imports this data > from Yahoo finance, the Date column is automatically transformed to Y-m-d, > whereis in the data it appears as m/d/Y: > > myData <- > read.csv("http://ichart.finance.yahoo.com/table.csv?s=GOOG&a=07&b=19&c=2004&d=03&e=16&f=2010&g=d&ignore=.csv") > > However, it does not actually convert the variable to Date format. > MyData$Date is still a factor. This combination of converting the format but > not attributing the 'Date' class is for me extremely unfortunate behavior. > My scripts still don't recognize the variable as being a date, but it also > becomes harder to manually convert it using as.Date() because it is no > longer in the original format. > > Is there a way to either automatically convert to as.Date() when a date > format has been detected, or otherwise disable this transformation at all? > > > -- > View this message in context: http://n4.nabble.com/read-table-behavior-for-Dates-tp2013442p2013442.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at 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. >
Try this: myData <- read.csv("http://ichart.finance.yahoo.com/table.csv?s=GOOG&a=07&b=19&c=2004&d=03&e=16&f=2010&g=d&ignore=.csv", colClasses = c('Date', rep('numeric', 6))) On Fri, Apr 16, 2010 at 4:32 PM, Jeroen Ooms <jeroenooms at gmail.com> wrote:> > When read.table imports a table that includes a header called 'Date', it > tries to recognize the date format. For example, if one imports this data > from Yahoo finance, the Date column is automatically transformed to Y-m-d, > whereis in the data it appears as m/d/Y: > > myData <- > read.csv("http://ichart.finance.yahoo.com/table.csv?s=GOOG&a=07&b=19&c=2004&d=03&e=16&f=2010&g=d&ignore=.csv") > > However, it does not actually convert the variable to Date format. > MyData$Date is still a factor. This combination of converting the format but > not attributing the 'Date' class is for me extremely unfortunate behavior. > My scripts still don't recognize the variable as being a date, but it also > becomes harder to manually convert it using as.Date() because it is no > longer in the original format. > > Is there a way to either automatically convert to as.Date() when a date > format has been detected, or otherwise disable this transformation at all? > > > -- > View this message in context: http://n4.nabble.com/read-table-behavior-for-Dates-tp2013442p2013442.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at 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. >-- Henrique Dallazuanna Curitiba-Paran?-Brasil 25? 25' 40" S 49? 16' 22" O