Fastest way to replace NAs in a large data.table

Question

I have a large data.table, with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as

Answer 1

Here is a solution using NAToUnknown in the gdata package. I have used Andrie's solution to create a huge data table and also included time comparisons with Andrie's solution.

# CREATE DATA TABLE
dt1 = create_dt(2e5, 200, 0.1)

# FUNCTIONS TO SET NA TO ZERO   
f_gdata  = function(dt, un = 0) gdata::NAToUnknown(dt, un)
f_Andrie = function(dt) remove_na(dt)

# COMPARE SOLUTIONS AND TIMES
system.time(a_gdata  <- f_gdata(dt1))

user  system elapsed 
4.224   2.962   7.388 

system.time(a_andrie <- f_Andrie(dt1))

 user  system elapsed 
4.635   4.730  20.060 

identical(a_gdata, g_andrie)  

TRUE