[datatable-help] fread() coercing to character when seeing NA

[Harish]

Hi,

I am trying to get fread() to read NA without coercing the entire column to character, but I am unable to do it.  Please tell me whether I am doing something wrong or this is a bug.

# Load two data tables with a column of integers -- one with NA and one without

dt1 <- fread( "a\n2\n4\n8\n5", na.strings=c("?") )
dt2 <- fread( "a\n2\n4\n?\n5", na.strings=c("?") )


# The contents of both are as expected (or so it seems)
dt1
dt2

# The class of the column with NA is character
class( dt1$a )
class( dt2$a )    # Not expecting this to be character

# Even setting colClasses does not help

dt3 <- fread( "a\n2\n4\n?\n5", na.strings=c("?"), colClasses=c(a="integer") )
class( dt3$a )



Thanks for your help.

Regards,
Harish
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