On Tue, 12 May 2009, Mark Na wrote:
H R-helpers,I am using the following code to make a dataframe from an Excel spreadsheet: library(RODBC) channel <- odbcConnectExcel("Spreadsheet.xls") Data <- sqlFetch(channel, "Tab1") odbcClose(channel) One column (several, actually) in the spreadsheet contains integers in its first few rows but later values in these columns contain a mixture of numbers, letters and symbols (it's an ID variable, containing e.g., 12, 14, 19, 19B, 19C, 19/20) R creates this column as a numeric variable (I think because its first few variables are numbers) but as soon as R gets to the non-numeric values (e.g., 19/20) it replaces them with NA.
R doesn't do that: nor does RODBC. You can try reading the column with 'as.is = TRUE' (see ?sqlFetch), but this looks like a well-known Excel/ODBC driver bug where Excel decides the column is numeric based on the first few entries and hence exports it as numbers (and NULLs, the SQL version of NAs).
So, my question is: how can I specify that certain columns are to be read as character variables BEFORE the dataframe is created?
You can try specifying the column type in Excel, so it is recorded on the spreadsheet. I am not sure that works in all cases.
I have tried using as.character() in the third line (above) but it creates a very long first column containing all of my data... Thanks for any help you might provide, Mark Na ______________________________________________ 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.
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