johnmyleswhite

JMWMacBookPro:CSVTools johnmyleswhite$ julia test/benchmark.jl 
0.201432656
0.206143505
0.204748861
0.201648006
0.204058938
0.200518181
0.208433545
0.19637816
0.210459992

johnmyleswhite

immutable NullableVector{T}
    isnull::BitVector
    values::Vector{T}
end

Base.length(nv::NullableVector) = length(nv.isnull)

function Base.getindex(nv::NullableVector{Float64}, i::Integer)
    if nv.isnull[i]
        return Nullable{Float64}()

johnmyleswhite

function replace(s::String, pos::Integer, val::Char)
    io = IOBuffer()
    i = 0
    for c in s
        i += 1
        if i != pos
            write(io, c)
        else
            write(io, val)
        end

johnmyleswhite

> 2147483647L + 1L
[1] NA
Warning message:
In 2147483647L + 1L : NAs produced by integer overflow

> 46341L * 46341L
[1] NA
Warning message:
In 46341L * 46341L : NAs produced by integer overflow

johnmyleswhite

johnmyleswhite

##############################################################################
# Problem 1: SELECT COUNT(DISTINCT(column_1)) from table_1
##############################################################################

# Ideally, solution should look something like the following code

function count_distinct(table::TabularData)
    values = Set{eltype(table.column_1)}()
    for value in table.column_1
        push!(values, value)

johnmyleswhite

               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.4.0-dev+4878 (2015-05-17 18:08 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit b3116d4 (0 days old master)
|__/                   |  x86_64-apple-darwin14.3.0

julia> xs = [1, 2, 3]

johnmyleswhite

# Implement the unary operators: +, -, !, and ~
for f in (
    :(Base.(:+)),
    :(Base.(:-)),
    :(Base.(:!)),
    :(Base.(:~)),
)
    @eval begin
        function $(f){S}(x::Nullable{S})
            resval = $(f)(x.value)

johnmyleswhite

• C# spec: http://www.microsoft.com/en-US/download/details.aspx?id=7029
• Hack references: http://docs.hhvm.com/manual/en/hack.nullable.php
• Swift optionals: http://www.matt.digital/comparing-c-nullable-types-and-swift-optionals/
• Rust option: https://doc.rust-lang.org/std/option/
• Scala option: http://www.scala-lang.org/api/current/scala/Option.html
• Haskell maybe: https://hackage.haskell.org/package/base-4.2.0.1/docs/Data-Maybe.html
• SQL NULL: http://en.wikipedia.org/wiki/Null_(SQL)
• Dart DEP: https://github.com/chalin/DEP-non-null/blob/master/doc/dep-non-null-AUTOGENERATED-DO-NOT-EDIT.md

johnmyleswhite

# Implement the unary operators: +, -, !, and ~

using NullableArrays

@noinline throw_error() = error()

for f in (
    :(Base.(:+)),
    :(Base.(:-)),
    :(Base.(:!)),