adde sample codes.

Author: mono0926

1261_02_Code/1261_2_01-basic_class.py

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+class MyFirstClass:
+    pass

1261_02_Code/1261_2_02-instantiate_basic_class.py

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+class MyFirstClass:
+    pass
+
+a = MyFirstClass()
+b = MyFirstClass()
+print(a)
+print(b)

1261_02_Code/1261_2_03_attributes.py

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+class Point:
+    pass
+
+p1 = Point()
+p2 = Point()
+
+p1.x = 5
+p1.y = 4
+
+p2.x = 3
+p2.y = 6
+
+print(p1.x, p1.y)
+print(p2.x, p2.y)

1261_02_Code/1261_2_04-first_method.py

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+class Point:
+    def reset(self):
+        self.x = 0
+        self.y = 0
+
+p = Point()
+p.reset()
+print(p.x, p.y)

1261_02_Code/1261_2_05-invoking_method_statically.py

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+class Point:
+    def reset(self):
+        self.x = 0
+        self.y = 0
+
+p = Point()
+Point.reset(p)
+print(p.x, p.y)

1261_02_Code/1261_2_06-methods_with_arguments.py

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+import math
+
+class Point:
+    def move(self, x, y):
+        self.x = x
+        self.y = y
+    def reset(self):
+        self.move(0, 0)
+    def calculate_distance(self, other_point):
+        return math.sqrt(
+                (self.x - other_point.x)**2 +
+                (self.y - other_point.y)**2)
+
+
+# how to use it:
+point1 = Point()
+point2 = Point()
+
+point1.reset()
+point2.move(5,0)
+print(point2.calculate_distance(point1))
+assert (point2.calculate_distance(point1) ==
+        point1.calculate_distance(point2))
+point1.move(3,4)
+print(point1.calculate_distance(point2))
+print(point1.calculate_distance(point1))

1261_02_Code/1261_2_07-initialization_function.py

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+class Point:
+    def __init__(self, x, y):
+        self.move(x, y)
+
+    def move(self, x, y):
+        self.x = x
+        self.y = y
+
+    def reset(self):
+        self.move(0, 0)
+
+# Constructing a Point
+point = Point(3, 5)
+print(point.x, point.y)

1261_02_Code/1261_2_08-initialization_defaults.py

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+class Point:
+    def __init__(self, x=0, y=0):
+        self.move(x, y)

1261_02_Code/1261_2_09-docstrings.py

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+import math
+
+class Point:
+    'Represents a point in two-dimensional geometric coordinates'
+
+    def __init__(self, x=0, y=0):
+        '''Initialize the position of a new point. The x and y coordinates can
+        be specified. If they are not, the point defaults to the origin.'''
+        self.move(x, y)
+
+    def move(self, x, y):
+        "Move the point to a new location in two-dimensional space."
+        self.x = x
+        self.y = y
+
+    def reset(self):
+        'Reset the point back to the geometric origin: 0, 0'
+        self.move(0, 0)
+
+    def calculate_distance(self, other_point):
+        """Calculate the distance from this point to a second point passed
+        as a parameter.
+
+        This function uses the Pythagorean Theorem to calculate the distance
+        between the two points.  The distance is returned as a float."""
+
+        return math.sqrt(
+                (self.x - other_point.x)**2 +
+                (self.y - other_point.y)**2)

1261_02_Code/1261_2_10-database_module-level-global.py

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+class Database:
+    # the database implementation
+    pass
+
+database = Database()

1261_02_Code/1261_2_11-database_module-level-global-initializer.py

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+class Database:
+    # the database implementation
+    pass
+
+database = None
+
+def initialize_database():
+    global database
+    database = Database()

1261_02_Code/1261_2_12-main-example.py

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+class UsefulClass:
+    '''This class might be useful to other modules.'''
+    pass
+
+def main():
+    '''creates a useful class and does something with it for our module.'''
+    useful = UsefulClass()
+    print(useful)
+
+if __name__ == "__main__":
+    main()

1261_02_Code/1261_2_13-class_in_function.py

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+def format_string(string, formatter=None):
+    '''Format a string using the formatter object, which
+    is expected to have a format() method that accepts
+    a string.'''
+    class DefaultFormatter:
+        '''Format a string in title case.'''
+        def format(self, string):
+            return str(string).title()
+
+    if not formatter:
+        formatter = DefaultFormatter()
+
+    return formatter.format(string)
+
+hello_string = "hello world, how are you today?"
+print(" input: " + hello_string)
+print("output: " + format_string(hello_string))

1261_02_Code/1261_2_14-name_mangling.py

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+class SecretString:
+    '''A not-at-all secure way to store a secret string.'''
+
+    def __init__(self, plain_string, pass_phrase):
+        self.__plain_string = plain_string
+        self.__pass_phrase = pass_phrase
+
+    def decrypt(self, pass_phrase):
+        '''Only show the string if the pass_phrase is correct.'''
+        if pass_phrase == self.__pass_phrase:
+            return self.__plain_string
+        else:
+            return ''

1261_02_Code/1261_2_15-note_object.py

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+import datetime
+
+last_id = 0
+
+class Note:
+    '''Represent a note in the notebook. Match against a
+    string in searches and store tags for each note.'''
+
+
+    def __init__(self, memo, tags=''):
+        '''initialize a note with memo and optional
+        space-separated tags. Automatically set the note's
+        creation date and a unique id'''
+        self.memo = memo
+        self.tags = tags
+        self.creation_date = datetime.date.today()
+        global last_id
+        last_id += 1
+        self.id = last_id
+
+    def match(self, filter):
+        '''Determine if this note matches the filter
+        text. Return True if it matches, False otherwise.
+        
+        Search is case sensitive and matches both text and
+        tags.'''
+        return filter in self.memo or filter in self.tags

1261_02_Code/1261_2_16-notebook_first.py

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+class Notebook:
+    '''Represent a collection of notes that can be tagged,
+    modified, and searched.'''
+
+    def __init__(self):
+        '''Initialize a notebook with an empty list.'''
+        self.notes = []
+
+    def new_note(self, memo, tags=''):
+        '''Create a new note and add it to the list.'''
+        self.notes.append(Note(memo, tags))
+
+    def modify_memo(self, note_id, memo):
+        '''Find the note with the given id and change its
+        memo to the given value.'''
+        for note in self.notes:
+            if note.id == note_id:
+                note.memo = memo
+                break
+
+    def modify_tags(self, note_id, tags):
+        '''Find the note with the given id and change its
+        tags to the given value.'''
+        for note in self.notes:
+            if note.id == note_id:
+                note.tags = tags
+                break
+
+    def search(self, filter):
+        '''Find all notes that match the given filter
+        string.'''
+        return [note for note in self.notes if
+                note.match(filter)]

1261_02_Code/1261_2_17-notebook_findnote_method.py

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+    def _find_note(self, note_id):
+        '''Locate the note with the given id.'''
+        for note in self.notes:
+            if note.id == note_id:
+                return note
+        return None
+
+    def modify_memo(self, note_id, memo):
+        '''Find the note with the given id and change its
+        memo to the given value.'''
+        self._find_note(note_id).memo = memo

1261_02_Code/1261_2_18-notebook_menu.py

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+import sys
+from notebook import Notebook, Note
+
+class Menu:
+    '''Display a menu and respond to choices when run.'''
+    def __init__(self):
+        self.notebook = Notebook()
+        self.choices = {
+                "1": self.show_notes,
+                "2": self.search_notes,
+                "3": self.add_note,
+                "4": self.modify_note,
+                "5": self.quit
+                }
+
+    def display_menu(self):
+        print("""
+Notebook Menu
+
+1. Show all Notes
+2. Search Notes
+3. Add Note
+4. Modify Note
+5. Quit
+""")
+
+    def run(self):
+        '''Display the menu and respond to choices.'''
+        while True:
+            self.display_menu()
+            choice = input("Enter an option: ")
+            action = self.choices.get(choice)
+            if action:
+                action()
+            else:
+                print("{0} is not a valid choice".format(choice))
+
+    def show_notes(self, notes=None):
+        if not notes:
+            notes = self.notebook.notes
+        for note in notes:
+            print("{0}: {1}\n{2}".format(
+                note.id, note.tags, note.memo))
+
+    def search_notes(self):
+        filter = input("Search for: ")
+        notes = self.notebook.search(filter)
+        self.show_notes(notes)
+
+    def add_note(self):
+        memo = input("Enter a memo: ")
+        self.notebook.new_note(memo)
+        print("Your note has been added.")
+
+    def modify_note(self):
+        id = input("Enter a note id: ")
+        memo = input("Enter a memo: ")
+        tags = input("Enter tags: ")
+        if memo:
+            self.notebook.modify_memo(id, memo)
+        if tags:
+            self.notebook.modify_tags(id, tags)
+
+    def quit(self):
+        print("Thank you for using your notebook today.")
+        sys.exit(0)
+
+if __name__ == "__main__":
+    Menu().run()

1261_02_Code/1261_2_19-findnote_str.py

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+    def _find_note(self, note_id):
+        '''Locate the note with the given id.'''
+        for note in self.notes:
+            if str(note.id) == str(note_id):
+                return note
+        return None

1261_02_Code/1261_2_20-notebook_modify_sanity_check.py

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+    def modify_memo(self, note_id, memo):
+        '''Find the note with the given id and change its
+        memo to the given value.'''
+        note = self._find_note(note_id)
+        if note:
+            note.memo = memo
+            return True
+        return False