require 'daru'
samples = 1000

# We set lazy_update to *true* so that time is not wasted in updating
# metdata every time an assignment happens.
Daru.lazy_update = true
# The 'new_with_size' function lets you specify the size of the 
# vector as the argument and the block specifies how each element
# of the vector will be created.
a = Daru::Vector.new_with_size(samples) {r=rand(5); r==4 ? nil: r}
b = Daru::Vector.new_with_size(samples) {r=rand(5); r==4 ? nil: r}

# Call `#update` for updating the metadata of each vector, once 
# creation from the block is complete.
a.update
b.update

# Pass the Daru::Vector objects in a Hash to the DataFrame constructor
# to make a DataFrame.
# 
# The *order* option lets you specify the way the vectors in the Hash 
# will be ordered. Not specifyin this will order vectors in alphabetical
# order by default.
ds = Daru::DataFrame.new({:a=>a,:b=>b}, order: [:b, :a])

# Reset lazy_update to *false* to prevent other code from breaking.
Daru.lazy_update = false

ds