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+---
+language: julia
+author: Leah Hanson
+author_url: http://leahhanson.us
+---
+
+Julia is a new homoiconic functional language focused on technical computing.
+While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python.
+
+This is based on the current development version of Julia, as of June 29th, 2013.
+
+```julia
+# Single line comments start with a hash.
+
+####################################################
+## 1. Primitive Datatypes and Operators
+####################################################
+
+# Everything in Julia is a expression.
+
+# You have numbers
+3 #=> 3 (Int64)
+3.2 #=> 3.2 (Float64)
+2 + 1im #=> 2 + 1im (Complex{Int64})
+2//3 #=> 2//3 (Rational{Int64})
+
+# Math is what you would expect
+1 + 1 #=> 2
+8 - 1 #=> 7
+10 * 2 #=> 20
+35 / 5 #=> 7.0
+5 \ 35 #=> 7.0
+5 / 2 #=> 2.5
+div(5, 2) #=> 2
+2 ^ 2 #=> 4
+12 % 10 #=> 2
+
+# Enforce precedence with parentheses
+(1 + 3) * 2 #=> 8
+
+# Bitwise Operators
+~2 #=> -3   # bitwise not
+3 & 5 #=> 1 # bitwise and
+2 | 4 #=> 6 # bitwise or
+2 $ 4 #=> 6 # bitwise xor
+2 >>> 1 #=> 1 # logical shift right
+2 >> 1  #=> 1 # arithmetic shift right
+2 << 1  #=> 4 # logical/arithmetic shift left
+
+# You can use the bits function to see the binary representation of a number.
+bits(2)   #=> "0000000000000000000000000000000000000000000000000000000000000010"
+bits(2.0) #=> "0100000000000000000000000000000000000000000000000000000000000000"
+
+# Boolean values are primitives
+true
+false
+
+# Boolean operators
+!true #=> false
+!false #=> true
+1 == 1 #=> true
+2 == 1 #=> false
+1 != 1 #=> false
+2 != 1 #=> true
+1 < 10 #=> true
+1 > 10 #=> false
+2 <= 2 #=> true
+2 >= 2 #=> true
+# Comparisons can be chained
+1 < 2 < 3 #=> true
+2 < 3 < 2 #=> false
+
+# Strings are created with "
+"This is a string."
+
+# Character literals written with '
+'a'
+
+# A string can be treated like a list of characters
+"This is a string"[1] #=> 'T' # Julia indexes from 1
+
+# $ can be used for string interpolation:
+"2 + 2 = $(2+2)" # => "2 + 2 = 4"
+# You can put any Julia expression inside the parenthesis.
+
+# Another way to format strings is the printf macro.
+@printf "%d is less than %f" 4.5 5.3 # 5 is less than 5.300000
+
+####################################################
+## 2. Variables and Collections
+####################################################
+
+# Printing is pretty easy
+println("I'm Julia. Nice to meet you!")
+
+# No need to declare variables before assigning to them.
+some_var = 5 #=> 5 
+some_var #=> 5
+# Accessing a previously unassigned variable is an error
+some_other_var #=> ERROR: some_other_var not defined
+
+# Variable Names:
+Some!Other1Var! = 6 #=> 6 # You can use uppercase letters, digits, and exclamation points as well.
+☃ = 8 #=> 8 # You can also use unicode characters
+
+# A note on naming conventions in Julia:
+# * Names of variables are in lower case, with word separation indicated by underscores ('\_').
+# * Names of Types begin with a capital letter and word separation is shown with CamelCase instead of underscores.
+# * Names of functions and macros are in lower case, without underscores.
+# * Functions that modify their inputs have names that end in !. These functions are sometimes called mutating functions or in-place functions.
+
+
+# Arrays store sequences
+li = Int64[] #=> 0-element Int64 Array
+# 1-dimensional array literals can be written with comma-separated values.
+other_li = [4, 5, 6] #=> 3-element Int64 Array: [4, 5, 6]
+# 2-dimentional arrays use space-separated values and semicolon-separated rows.
+matrix = [1 2; 3 4] #=> 2x2 Int64 Array: [1 2; 3 4]
+
+# Add stuff to the end of a list with push! and append!
+push!(li,1)     #=> [1]
+push!(li,2)     #=> [1,2]
+push!(li,4)     #=> [1,2,4]
+push!(li,3)     #=> [1,2,4,3]
+append!(li,other_li) #=> [1,2,4,3,4,5,6]
+# Remove from the end with pop
+pop!(other_li)        #=> 6 and other_li is now [4,5]
+# Let's put it back
+push!(other_li,6)   # other_li is now [4,5,6] again.
+
+# Remember that Julia indexes from 1, not 0!
+li[1] #=> 1
+
+# Function names that end in exclamations points indicate that they modify their argument.
+arr = [5,4,6] #=> 3-element Int64 Array: [5,4,6]
+sort(arr) #=> [4,5,6]; arr is still [5,4,6]
+sort!(arr) #=> [4,5,6]; arr is now [4,5,6]
+
+# Looking out of bounds is a BoundsError
+li[0] # ERROR: BoundsError() in getindex at array.jl:270
+# Errors list the line and file they came from, even if it's in the standard library.
+# If you built Julia from source, you can look in the folder base inside the julia folder to find these files.
+
+# You can initialize arrays from ranges
+li = [1:5] #=> 5-element Int64 Array: [1,2,3,4,5]
+
+# You can look at ranges with slice syntax.
+li[1:3] #=> [1, 2, 3]
+# Omit the beginning
+li[2:] #=> [2, 3, 4, 5]
+
+# Remove arbitrary elements from a list with splice!
+splice!(li,2) #=> 2 ; li is now [1, 3, 4, 5]
+
+# Concatenate lists with append! 
+other_li = [1,2,3]
+append!(li,other_li) # Now li is [1, 3, 4, 5, 1, 2, 3]
+
+# Check for existence in a list with contains 
+contains(li,1) #=> true
+
+# Examine the length with length
+length(li) #=> 7
+
+# Tuples are like lists but are immutable.
+tup = (1, 2, 3)
+tup[0] #=> 1
+try:
+    tup[0] = 3  # Raises a TypeError
+except TypeError:
+    print "Tuples cannot be mutated."
+
+# You can do all those list thingies on tuples too
+len(tup) #=> 3
+tup + (4, 5, 6) #=> (1, 2, 3, 4, 5, 6)
+tup[:2] #=> (1, 2)
+2 in tup #=> True
+
+# You can unpack tuples into variables
+a, b, c = (1, 2, 3)     # a is now 1, b is now 2 and c is now 3
+# Tuples are created by default if you leave out the parentheses
+d, e, f = 4, 5, 6
+# Now look how easy it is to swap two values
+e, d = d, e     # d is now 5 and e is now 4
+
+
+# Dictionaries store mappings
+empty_dict = {}
+# Here is a prefilled dictionary
+filled_dict = {"one": 1, "two": 2, "three": 3}
+
+# Look up values with []
+filled_dict["one"] #=> 1
+
+# Get all keys as a list
+filled_dict.keys() #=> ["three", "two", "one"]
+# Note - Dictionary key ordering is not guaranteed.
+# Your results might not match this exactly.
+
+# Get all values as a list
+filled_dict.values() #=> [3, 2, 1]
+# Note - Same as above regarding key ordering.
+
+# Check for existence of keys in a dictionary with in
+"one" in filled_dict #=> True
+1 in filled_dict #=> False
+
+# Trying to look up a non-existing key will raise a KeyError
+filled_dict["four"] #=> KeyError
+
+# Use get method to avoid the KeyError
+filled_dict.get("one") #=> 1
+filled_dict.get("four") #=> None
+
+# The get method supports a default argument when the value is missing
+filled_dict.get("one", 4) #=> 1
+filled_dict.get("four", 4) #=> 4
+
+# Setdefault method is a safe way to add new key-value pair into dictionary
+filled_dict.setdefault("five", 5) #filled_dict["five"] is set to 5
+filled_dict.setdefault("five", 6) #filled_dict["five"] is still 5
+
+
+# Sets store ... well sets
+empty_set = set()
+# Initialize a set with a bunch of values
+some_set = set([1,2,2,3,4]) # filled_set is now set([1, 2, 3, 4])
+
+# Since Python 2.7, {} can be used to declare a set
+filled_set = {1, 2, 2, 3, 4} # => {1 2 3 4}
+
+# Add more items to a set
+filled_set.add(5) # filled_set is now {1, 2, 3, 4, 5}
+
+# Do set intersection with &
+other_set = set{3, 4, 5, 6}
+filled_set & other_set #=> {3, 4, 5}
+
+# Do set union with |
+filled_set | other_set #=> {1, 2, 3, 4, 5, 6}
+
+# Do set difference with -
+{1,2,3,4} - {2,3,5} #=> {1, 4}
+
+# Check for existence in a set with in
+2 in filled_set #=> True
+10 in filled_set #=> False
+
+
+####################################################
+## 3. Control Flow
+####################################################
+
+# Let's just make a variable
+some_var = 5
+
+# Here is an if statement. INDENTATION IS SIGNIFICANT IN PYTHON!
+# prints "some var is smaller than 10"
+if some_var > 10:
+    print "some_var is totally bigger than 10."
+elif some_var < 10:    # This elif clause is optional.
+    print "some_var is smaller than 10."
+else:           # This is optional too.
+    print "some_var is indeed 10."
+
+
+"""
+For loops iterate over lists
+prints:
+    dog is a mammal
+    cat is a mammal
+    mouse is a mammal
+"""
+for animal in ["dog", "cat", "mouse"]:
+    # You can use % to interpolate formatted strings
+    print "%s is a mammal" % animal
+
+"""
+While loops go until a condition is no longer met.
+prints:
+    0
+    1
+    2
+    3
+"""
+x = 0
+while x < 4:
+    print x
+    x += 1  # Shorthand for x = x + 1
+
+# Handle exceptions with a try/except block
+
+# Works on Python 2.6 and up:
+try:
+    # Use raise to raise an error
+    raise IndexError("This is an index error")
+except IndexError as e:
+    pass    # Pass is just a no-op. Usually you would do recovery here.
+
+# Works for Python 2.7 and down:
+try:
+    raise IndexError("This is an index error")
+except IndexError, e: # No "as", comma instead
+    pass
+
+
+####################################################
+## 4. Functions
+####################################################
+
+# Use def to create new functions
+def add(x, y):
+    print "x is %s and y is %s" % (x, y)
+    return x + y    # Return values with a return statement
+
+# Calling functions with parameters
+add(5, 6) #=> 11 and prints out "x is 5 and y is 6"
+# Another way to call functions is with keyword arguments
+add(y=6, x=5)   # Keyword arguments can arrive in any order.
+
+# You can define functions that take a variable number of
+# positional arguments
+def varargs(*args):
+    return args
+
+varargs(1, 2, 3) #=> (1,2,3)
+
+
+# You can define functions that take a variable number of
+# keyword arguments, as well
+def keyword_args(**kwargs):
+    return kwargs
+
+# Let's call it to see what happens
+keyword_args(big="foot", loch="ness") #=> {"big": "foot", "loch": "ness"}
+
+# You can do both at once, if you like
+def all_the_args(*args, **kwargs):
+    print args
+    print kwargs
+"""
+all_the_args(1, 2, a=3, b=4) prints:
+    [1, 2]
+    {"a": 3, "b": 4}
+"""
+
+# You can also use * and ** when calling a function
+args = (1, 2, 3, 4)
+kwargs = {"a": 3, "b": 4}
+foo(*args) # equivalent to foo(1, 2, 3, 4)
+foo(**kwargs) # equivalent to foo(a=3, b=4)
+foo(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4)
+
+# Python has first class functions
+def create_adder(x):
+    def adder(y):
+        return x + y
+    return adder
+
+add_10 = create_adder(10)
+add_10(3) #=> 13
+
+# There are also anonymous functions
+(lambda x: x > 2)(3) #=> True
+
+# There are built-in higher order functions
+map(add_10, [1,2,3]) #=> [11, 12, 13]
+filter(lambda x: x > 5, [3, 4, 5, 6, 7]) #=> [6, 7]
+
+# We can use list comprehensions for nice maps and filters
+[add_10(i) for i in [1, 2, 3]]  #=> [11, 12, 13]
+[x for x in [3, 4, 5, 6, 7] if x > 5] #=> [6, 7]
+
+####################################################
+## 5. Classes
+####################################################
+
+# We subclass from object to get a class.
+class Human(object):
+
+     # A class attribute. It is shared by all instances of this class
+    species = "H. sapiens"
+
+    # Basic initializer
+    def __init__(self, name):
+        # Assign the argument to the instance's name attribute
+        self.name = name
+
+    # An instance method. All methods take self as the first argument
+    def say(self, msg):
+       return "%s: %s" % (self.name, msg)
+
+    # A class method is shared among all instances
+    # They are called with the calling class as the first argument
+    @classmethod
+    def get_species(cls):
+        return cls.species
+
+    # A static method is called without a class or instance reference
+    @staticmethod
+    def grunt():
+        return "*grunt*"
+
+
+# Instantiate a class
+i = Human(name="Ian")
+print i.say("hi")     # prints out "Ian: hi"
+
+j = Human("Joel")
+print j.say("hello")  #prints out "Joel: hello"
+
+# Call our class method
+i.get_species() #=> "H. sapiens"
+
+# Change the shared attribute
+Human.species = "H. neanderthalensis"
+i.get_species() #=> "H. neanderthalensis"
+j.get_species() #=> "H. neanderthalensis"
+
+# Call the static method
+Human.grunt() #=> "*grunt*"
+```
+
+## Further Reading
+
+Still up for more? Try [Learn Python The Hard Way](http://learnpythonthehardway.org/book/)
+