On 07/18/2020 11:54 AM, Rui Barradas wrote: > Hello, > > I don't believe that what you are asking for is possible but like Bert > suggested, you can do it after reading in the data. > You could write a convenience function to read the data, then change what you > need to change. > Then the function would return this final object. > > Rui Barradas > > Às 16:43 de 18/07/2020, H escreveu: > >> On 07/17/2020 09:49 PM, Bert Gunter wrote: >>> Is there some reason that you can't make the changes to the data frame >>> (column names, as.date(), ...) *after* you have read all your data in? >>> >>> Do all your csv files use the same names and date formats? >>> >>> >>> Bert Gunter >>> >>> "The trouble with having an open mind is that people keep coming along and >>> sticking things into it." >>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) >>> >>> >>> On Fri, Jul 17, 2020 at 6:28 PM H <age...@meddatainc.com >>> <mailto:age...@meddatainc.com>> wrote: >>> >>> I have created a dataframe with columns that are characters, integers >>> and numeric and with column names assigned by me. I am using read.csv.sql() >>> to read portions of a number of large csv files into this dataframe, each >>> csv file having a header row with columb names. >>> >>> The problem I am having is that the csv files have header rows with >>> column names that are slightly different from the column names I have >>> assigned in the dataframe and it seems that when I read the csv data into >>> the dataframe, the column names from the csv file replace the column names >>> I chose when creating the dataframe. >>> >>> I have been unable to figure out if it is possible to assign column >>> names of my choosing in the read.csv.sql() function? I have tried various >>> variations but none seem to work. I tried colClasses = c(....) but that did >>> not work, I tried field.types = c(...) but could not get that to work >>> either. >>> >>> It seems that the above should be feasible but I am missing something? >>> Does anyone know? >>> >>> A secondary issue is that the csv files have a column with a date in >>> mm/dd/yyyy format that I would like to make into a Date type column in my >>> dataframe. Again, I have been unable to find a way - if at all possible - >>> to force a conversion into a Date format when importing into the dataframe. >>> The best I have so far is to import is a character column and then use >>> as.Date() to later force the conversion of the dataframe column. >>> >>> Is it possible to do this when importing using read.csv.sql()? >>> >>> ______________________________________________ >>> R-help@r-project.org <mailto:R-help@r-project.org> mailing list -- To >>> UNSUBSCRIBE and more, see >>> 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. >>> >> Yes, the files use the same column names and date format (at least as far as >> I know now.) I agree I could do it as you suggest above but from a purist >> perspective I would rather do it when importing the data using >> read.csv.sql(), particularly if column names and/or date format might >> change, or be different between different files. I am indeed selecting rows >> from a large number of csv files so this is entirely plausible. >> >> Has anyone been able to name columns in the read.csv.sql() call and/or force >> date format conversion in the call itself? The first refers to naming >> columns differently from what a header in the csv file may have. >> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > The documentation for read.csv.sql() suggests that colClasses() and/or field.types() should work but I may well have misunderstood the documentation, hence my question in this group.
______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
