On 07/30/2020 06:09 PM, Gabor Grothendieck wrote:
> Probably simplest to assign the names afterwards as others have
> suggested but it could be done like this:
>
> library(sqldf)
> write.csv(BOD, "BOD.csv", quote = FALSE, row.names = FALSE) # test data
>
> read.csv.sql("BOD.csv", "select Time as Time2, demand as demand2 from file")
>
> giving the column names Time2 and demand2 rather than the original column
> names.
>
> Time2 demand2
> 1 1 8.3
> 2 2 10.3
> 3 3 19.0
> 4 4 16.0
> 5 5 15.6
> 6 7 19.8
>
> On Fri, Jul 17, 2020 at 9:28 PM H <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 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.
>
>
Apologies, I had tuned out from this discussion since I solved the problem by
renaming the columns after reading the file. Your suggestion to do it in the
SQL statement itself, however, seems to be neatest one though!
Thank you.
______________________________________________
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.
