preserve old (pre 3.1.0) type.convert behavior

Question

R 3.1.0 is out and one of the new features is the following:

type.convert() (and hence by default read.table()) returns a ch

Answer 1

Try using data.table's fread:

# create test data set "a.dat"
Lines <- "num1 num2\n1.1 1.1234567890123456\n2.2 2.2\n3.3 3.3\n"
cat(Lines, file = "a.dat")

#####

library(data.table)

DT <- fread("a.dat")
str(DT)
## Classes ‘data.table’ and 'data.frame':  3 obs. of  2 variables:
## $ num1: num  1.1 2.2 3.3
## $ num2: num  1.12 2.2 3.3
## - attr(*, ".internal.selfref")= 

class(DT)
## [1] "data.table" "data.frame"

DF <- as.data.frame(DT) 
class(DF)
## [1] "data.frame"

ADDED LATER Since this answer was posted the latest patched version of R 3.1.0 has come out and by default reverts back to the old behavior with a new numerals argument to specify it differently. See type.convert and read.table