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.