# This part will be explained later
using Pkg
Pkg.activate("..")
Pkg.instantiate();

a = 3
typeof(a)

a = 3.0
typeof(a)

a = convert(Float64, 2)
typeof(a)

a = "3"
typeof(a)

ab = "a"*"b"

"a = $a"

s = :foo
typeof(s)

x = [1,2,3,4]

x = [1 2 3 4]

X = [1 2; 3 4]

X = zeros(2,3)
Y = ones(2,3)
Z = randn(2,3)

A = [3 2 1; 2 3 2; 1 2 3]
x = [0, 1, 2]
b = A*x

c = x'*A*x

 3 .*[1 2 3]

sin.([1., 2., 3.])

for n = 1:2:5
    println(n)
end

num_range = range(0, stop=4, length=2)
for n in num_range
    println(n)
end

for (j,n) in enumerate(num_range)
    println("$j, $n")
end

["n = $n" for n in num_range]

a = 3.0
if a < 0 
    println("Negative")
elseif a == 0
    println("0.0")
else 
    println("Positive")
end

a > 0 ? println("Positive") : println("Not positive")

function foo(bar::Float64)
    message = "Boo!"
    return message
end

function foo(bar::Integer)
    message = "Bah!"
    return message
end

foo(1)

fn(x::Number) = 1/x
fn(4)

fn(; number::Number = 1) = 1/number
[fn() fn(number=3)]

x = [1, 3, 2]
[sort(x) x]

[sort!(x) x]

using Pkg
Pkg.activate("..")
Pkg.instantiate();

using LinearAlgebra

E,V = eigen([3. 2.;2. 0.4])

using DataFrames

x = Dict(
    "a" => 1,
    "b" => 2,
    "c" => 3
)

df = DataFrame(x)

using Distributions

px = Normal(1.0, 0.5)
pdf(px, 0.0)

using Plots

x = range(-3, stop=3, length=301)
plot(x, pdf.(px, x), xlabel="x", ylabel="p(x)", label="pdf", color="red", linewidth=5, linestyle=:dash)

X = randn(10,2)
scatter(X[:,1], X[:,2], xlabel="X_1", ylabel="X_2", markersize=10, markershape=:cross)

plot(x, pdf.(Normal(0.,1.), x), xlabel="x", ylabel="p(x)", label="N(0,1)", color="red", linewidth=5, linestyle=:dash)
plot!(x, pdf.(Normal(1.,0.5), x), xlabel="x", ylabel="p(x)", label="N(1,0.5)", color="blue", linestyle=:solid)

using ProgressMeter

@showprogress for n in 1:10
    sleep(0.1)
end

function add1(a::Integer)
    return a + 1
end

add1(3.0)

add1(3)

function add(a::Integer, b::Integer)
    return a+b
end

add(3.0,4)

add(3,4)

y = 3*aa

aa = MvNormalMeanVariance()

yy = 3*2
zz = 3*yy
xx = yy*xx
zz = yy*xx