First pass at moving part4 to markdown. Updated sedscr some. Still bad

Author: calebsmith

sedscr

@@ -3,15 +3,17 @@
 # sed -f sedscr filename.html > filename.md
 /^ *$/d
 /<section>/d
-s/.*<\/section>/@@@\n\n/g
+s/.*<\/section>/@@@\n/g
 s/.*<!--/Note: /
 s/-->//
 s/.*<h1>/#/
-s/<\/h1>/\n/
+s/<\/h1>//
 s/.*<h2>/##/
-s/<\/h2>/\n/
+s/<\/h2>//
 s/.*<h3>/###/
-s/<\/h3>/\n/
+s/<\/h3>//
+s/.*<h4>/####/
+s/<\/h4>//
 s/.*<li>/* /
 s/<\/li>/\n/
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@@ -30,3 +32,4 @@ s/.*<\/code><\/pre>/```/
     s/\[(/[/
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+s/.*<img src="\(.*\)" \/>/[](\1)/

set2/slides/menu.md

@@ -6,5 +6,6 @@
 [Section 1](?part=part1)
 [Section 2](?part=part2)
 [Section 3](?part=part3)
+[Section 4](?part=part4)
 <div class="clearfix"> </div>
 [Contents](?part=contents)

set2/slides/part4.md

@@ -0,0 +1,363 @@
+![Girl Develop It logo](../images/gdi_logo_badge.png)
+###Intro to Python
+####Class 4
+@@@
+
+###Review
+
+* Method calls
+
+* Combining lists and dictionaries
+
+* Builtins for collections
+
+@@@
+
+###Functions on Dictionaries
+
+```python
+character = {
+    'x': 10,
+    'y': 20,
+    'health': 100,
+}
+def injure(character, damage):
+    character['health'] = character['health'] - damage
+    if character['health'] < 0:
+        character['health'] = 0
+def heal(character, amount):
+    character['health'] = character['health'] + amount
+    if character['health'] > 100:
+        character['health'] = 100
+```
+Note:  Block 1  - Intro to Classes and OOP - 20 minutes
+@@@
+
+###Classes
+A <strong>class</strong> creates a new type of object.
+
+A class defines the attributes and methods of objects of that type
+
+Classes are used to create new objects of that type
+
+```python
+class Character():
+    def __init__(self, x, y, health):
+        self.x = x
+        self.y = y
+        self.health = health
+character = Character(10, 20, 100)
+```
+@@@
+
+###A Sense of Self
+The first argument to every method is <strong>self</strong>.
+
+self contains the attributes and methods for the current object
+
+```python
+class Character():
+    def __init__(self, x, y, health):
+        self.x = x
+        self.y = y
+        self.health = health
+character = Character(10, 20, 100)
+```
+@@@
+
+###The __init__ Method
+This method defines what the class should do when creating a new object.
+
+```python
+class Character():
+    def __init__(self, x, y, health):
+        self.x = x
+        self.y = y
+        self.health = health
+character_a = Character(10, 20, 100)
+character_b = Character(10, 20, 100)
+```
+To create a new Character, the syntax looks like a function call. These arguments are passed to the __init__ method
+
+@@@
+
+###Class Methods
+A class also defines <strong>methods</strong>, which are functions that operate on objects of that type
+
+Assigning values to an attribute on self is how we <strong>mutate</strong> the object's state.
+
+```python
+# inside the character class
+    def heal(self, amount):
+        self.health = self.health + amount
+        if self.health > 100:
+            self.health = 100
+    def injure(self, amount):
+        self.health = self.health - amount
+        if self.health < 0:
+           self.health = 0
+character = Character(10, 20, 100)
+character.injure(10)
+```
+@@@
+
+###Let's Develop It
+
+* In your text editor, create your own class with an __init__ method, and at least one other method.
+
+* Open a Python shell and import the class. Create one or more objects from the class
+
+* If time allows, create a function that creates objects from your class, calls a method, and prints one of its attributes
+
+* Use the next slide as an example
+
+Note:  Let's develop it: 10 minutes
+@@@
+
+```python
+# in character.py
+class Character():
+    def __init__(self, x, y, health):
+        self.x = x
+        self.y = y
+        self.health = health
+    def heal(self, amount):
+        self.health = self.health + amount
+        if self.health > 100:
+            self.health = 100
+```
+```python
+# in Python shell
+from character import Character
+character_a = Character(10, 20, 100)
+character_a.injure(10)
+print "character health is: " + character_a.health
+```
+@@@
+
+###Inheritance
+A class can <strong>inherit</strong> from another class.
+
+A class that inherits from another is called the "child class" and obtains the methods and attributes of its "parent"
+
+```python
+class Mobile(object):
+    """
+    An object with an x, y position, and methods for moving
+    """
+    def __init__(self, x, y):
+        self.x = x
+        self.y = y
+    def move_up():
+        self.y = self.y - 1
+    # ... methods for move_down, move_left, and move_right
+```
+Note:  Block 2 - Inheritance and Composition 20 Minutes
+@@@
+
+###Inheritance Continued
+The move_up method is <strong>overridden</strong> in the child class below:
+
+```python
+class BoundedMobile(Mobile):
+    """
+    An object with an x, y position, and methods for moving
+    The x, y position must be within bounds
+    """
+    def move_up():
+        self.y = self.y - 1
+        if self.y < 0:
+            self.y = 0
+```
+See [mobile.py](http://calebsmith.github.io/gdi-intro-python/examples/mobile.py) for a more complete example.
+
+@@@
+
+###What's Super about Super
+<strong>super</strong> is often helpful when writing methods that override the method of the parent class
+
+```python
+class BoundedMobile(Mobile):
+    """
+    An object with an x, y position, and methods for moving
+    The x, y position must be within bounds
+    """
+    def move_up():
+        super(BoundedMobile, self).move_up()
+        if self.y < 0:
+            self.y = 0
+```
+The call to super() takes the name of the child class, followed by self. This is followed by the method call and any arguments to pass to it
+
+@@@
+
+###Composition
+Classes can also use the technique of <strong>composition</strong>
+
+This simply means that a given object contains other objects within it.
+
+This often leads to a clearer and simpler design
+
+```python
+class Grid(object):
+    def __init__(self, x_limit, y_limit):
+        self.x_limit = x_limit
+        self.y_limit = y_limit
+        self.mobiles = []
+    def add_mobile(self, x, y):
+        mob = BoundedMobile(x, y, self.x_limit, self.y_limit)
+        mobs = self.mobiles.get((x, y), [])
+        mobs.append(mob)
+        self.mobiles[(x, y)] = mobs
+```
+@@@
+
+###Composition Continued
+Given the class on the previous slide, the following code creates mobiles within the grid object. (Complete code is available in the aforementioned [mobile.py](http://calebsmith.github.io/gdi-intro-python/examples/mobile.py))
+
+```python
+from mobile import Grid
+grid = Grid(7, 7)
+grid.add_mobile(1, 2)
+grid.add_mobile(0, 1)
+grid.add_mobile(0, 1)
+grid.display_grid()
+```
+@@@
+
+###Let's Develop It
+Create a class that uses inheritance, composition, or both.
+
+To help you, use your work from the last exercise or the classes from [mobile.py](http://calebsmith.github.io/gdi-intro-python/examples/mobile.py)
+
+Note:  Block 3 - Functional Programming - 20 Minutes
+@@@
+
+###List Comprehensions
+I have a list and I have something I want to do to each element to create a new list
+
+```python
+squares = []
+for number in range(11):
+    squares.append(number ** 2)
+```
+This pattern is so common, there is a shorter way to express it:
+
+```python
+squares = [number ** 2 for number in range(11)]
+```
+This is called a <strong>list comprehension</strong>
+Note:  Let's develop it: 10 minutes
+
+@@@
+
+###Generators
+A <strong>generator</strong> is like a list, but it is evaluated when it is used rather than when it is defined.
+
+Generators are useful when the list may be very large or when the task is time consuming
+
+```python
+#Define a generator
+def find_squares(numbers):
+    for number in numbers
+        yield number ** 2
+#Iterate on a generator like a list
+for square in find_squares(range(10)):
+    print square
+```
+A function with a <strong>yield</strong> statement creates a generator. Each yield statement "yields" the next value in the sequence
+
+@@@
+
+###Generator Comprehensions
+A <strong>generator comprehension</strong> is created the same way as list comprehension, but replacing the square brackets with parenthesis.
+
+```python
+ten_squares = (number ** 2 for number in range(10))
+```
+
+These are used liberally in the functions of [books.py](http://calebsmith.github.io/gdi-intro-python/examples/books.py) example from class 3.
+
+@@@
+
+###Higher order functions
+A <strong>higher order function</strong> is a function that returns a function, takes a function as an argument, or both
+
+One commonly used higher order function that is a Python builtin is called <strong>map</strong>
+
+```python
+# Define any function
+def sqaure(number):
+    return number ** 2
+# Pass the function to map along with an iterable
+squares = map(square, range(10))
+```
+@@@
+
+###Let's Develop It
+
+Choose among any of these projects (Resources available on the next page):
+
+* Search the Web - Write a program that searches the web using DuckDuckGo and displays results.
+
+* Encryption - Write a program that encrypts a string from user input, or file and is able to decrypt it as well.
+
+* Command Line Game - Create a simple game that runs inside the terminal.
+@@@
+
+###Let's Develop It Resources
+<table>
+    <tr>
+        <td>Search the Web</td>
+        <td>Use the [python-duckduckgo](https://github.com/crazedpsyc/python-duckduckgo/) library to get started. Download duckduckgo.py and put it in the same directory as your code. Use the query() function it provides to begin. (HINT: Results are often empty, but 'related' list usually has a few hits.)</td>
+    </tr>
+    <tr>
+        <td>Encryption</td>
+        <td>Read about the [Caesar Cipher](https://en.wikipedia.org/wiki/Caesar_cipher) or find a similarly simple encryption mechanism online. You should find the ord() and chr() functions helpful, as well as the modulus operator '%'</td>
+    </tr>
+</table>
+continued on next page...
+
+@@@
+
+###Let's Develop It Resources Continued
+
+<table>
+    <tr>
+        <td>Command Line Game</td>
+        <td>This might be a text adventure with paragraphs of text followed by a series of choices for the user. A choice maps to another node in the story (another paragraph with choices). You might try storing the paragraphs separately in a text file. The format might be something different, such as a series of "rooms", each with a description, for the user to explore by entering commands such as "go west". Examples of these kinds of games are [Colossal Cave Adventure](https://en.wikipedia.org/wiki/Colossal_Cave_Adventure) and <a href="https://en.wikipedia.org/wiki/Zor">Zork</a></td>
+    </tr>
+</table>
+@@@
+
+###Future Resources
+
+<table>
+    <tr>
+        <td>[Python.org Documentation](http://docs.python.org/2/)</td>
+        <td>Official Python Documentation</td>
+    </tr>
+    <tr>
+        <td>[Think Python](http://www.greenteapress.com/thinkpython/html/index.html)</td>
+        <td>Online and print book with exercises.</td>
+    </tr>
+    <tr>
+        <td>[Learn Python the Hard Way](http://learnpythonthehardway.org/book/)</td>
+        <td>Online and print book with exercises</td>
+    </tr>
+    <tr>
+        <td>[Google's Python Class](https://developers.google.com/edu/python/)</td>
+        <td>Video lectures coupled with exercises</td>
+    </tr>
+    <tr>
+        <td>[New Coder](http://newcoder.io/tutorials/)</td>
+        <td>Ideas for slightly larger projects and resources to get you started. Projects include accessing API's, scraping pages, writing IRC bots, and others.</td>
+    </tr>
+    <tr>
+        <td>[Girl Develop It](http://girldevelopit.com/)</td>
+        <td>Local workshops, events, and coding sessions</td>
+    </tr>
+</table>
+@@@
+
+###Questions?