juliatut2.txt

Julia Tutorial by Mike Sosa
Part 2: Functions, If/Else and More!

functions take on syntax like other lanuages
function name(arg1, arg2, ..... arg y)
  execution block
end

will begin with function, then the name of the function, then the input
arguments, then the execution block where you carry out what you want
and then an end declaration

ex. funcition add(x,y)
  x+y
end
you can also specify the type you want the inputs to be
ex.
  function add(x::type)
    println(x)
  end
can call with add(5,6) which will evaluate to 11
ex. x = add(5,6)
    x is 11

ex2. function add(x,y)
        return x + y
      end
will return the value of x + y

Returning multiple values
ex. function addmult(x,y)
      x+y, x*y
    end

ex. x = addmult(5,6)
    x will evaluate to (11,30)

operators as functions
Hint: They are
so you can do +(x,y,z) instead of x+y+z
or *(4,5)

you can also assign these to variable names
name=operator is the syntax
ex. addd=+
    add(2,3) evaluates to 5

functions are full class variables
you can assign other variables to functions
ex. g = f   # from before
    can use g(x,y)

Map function
Similar to ocaml. Can apply function to all elements in a list
ex. map(function(x)
      x*2
      end,
      [1,2,3]
    )
    returns 1 4 6
or can use syntax x -> x
ex. map(x -> x^3, [1,2,3])
  returns 2 4 6

Optional Arguments
can declare arguments that can be overwritten later
ex. function add2(r, s=6)
      r+s
    end
if s is specified it is overwritten, otherwise the default value of 6 is
used
ex. add2(5,4) evaluates to 9
ex. add2(5) evaluates to 11

Keyword agrs

need to define your variables
ex. function div(;x=10, y=5)
      x/y
    end
can call div(x=20,y=10) which evaluates to 2.0
order also doesn't matter div(y=10, x=20) also evaluates to 2.0


If/Else statements
Just like python

if condition
  do something
elseif condition2
  do something else
  .
  .
  .
else
  do something other
end

ex. x = 5
    if x < 20
      print "hi"
    end

Ternary operators
will evaluate condition and return either the first or second option
ex. x = 5
    print(x<0?"negative":"positive")
    will evaluate to posiitve