quick_convert.R

library(data.table)

size = 1e6
resample <- function(x,size = 1e6) sample(x,size,replace = TRUE)

text <- c("Canada","Peru","Australia","Angola","France","", NA_character_)
text2 <- c("Oh Canada.","Arriba Peru.","Australia?","Vive la France.")
numerics <- rnorm(1e6)

dt <- data.table(
  id = as.character(1:1e6),
  i1 = resample(c(as.character(c(0:5,NA)),"")), # sometimes just blank
  i2 = resample(c(as.character(c(100:500,NA)))),
  n1 = as.character(round(rnorm(1e6),3)),
  t1 = resample(text),
  t2 = resample(text2)
)

for(j in names(dt)) set(dt, j = j, value = type.convert(dt[[j]])
  
str(dt)