read.table vs fread

readtable_v_fread.R

# Generate dataset with 5,000,000 rows, and some random numbers from normal,
# uniform, and cauchy distributions. Write out to file (warning, ~330MB)
n <- 5000000
d <- data.frame(a=1:n, b=rnorm(n), c=runif(n), d=rcauchy(n))
write.table(d, file="test.txt")

# Import the regular way with read.table
system.time(in1 <- read.table("test.txt"))

## Crikey!
#    user  system elapsed 
# 132.164   0.786 132.917 

# Import with fread (Fast and friendly file finagler) in data.table package
library(data.table)
system.time(in2 <- fread("test.txt"))

# Wow. 
# Read 5000000 rows and 5 (of 5) columns from 0.334 GB file in 00:00:03
#    user  system elapsed 
#   2.049   0.094   2.141