Only read selected columns

Question

Can anyone please tell me how to read only the first 6 months (7 columns) for each year of the data below, for example by using read.table()?

Ye         


        

Answer 1

You do it like this:

df = read.table("file.txt", nrows=1, header=TRUE, sep="\t", stringsAsFactors=FALSE)
colClasses = as.list(apply(df, 2, class))
needCols = c("Year", "Jan", "Feb", "Mar", "Apr", "May", "Jun")
colClasses[!names(colClasses) %in% needCols] = list(NULL)
df = read.table("file.txt", header=TRUE, colClasses=colClasses, sep="\t", stringsAsFactors=FALSE)