data_table_colclasses.R

library("data.table")


fread("a,b\n1,T\n1,T\n1,T\n1,T\n1,T\n2,C\n")
#    a b
# 1: 1 1
# 2: 1 1
# 3: 1 1
# 4: 1 1
# 5: 1 1
# 6: 2 C

fread("a,b\n1,T\n1,T\n1,T\n1,T\n1,T\n2,C\n", 
      colClasses = list(character = c(2)))
#    a b
# 1: 1 T
# 2: 1 T
# 3: 1 T
# 4: 1 T
# 5: 1 T
# 6: 2 C