Chapter 1 Setup

import this

The Zen of Python, by Tim Peters
Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. Special cases aren’t special enough to break the rules. Although practicality beats purity. Errors should never pass silently. Unless explicitly silenced. In the face of ambiguity, refuse the temptation to guess. There should be one– and preferably only one –obvious way to do it. Although that way may not be obvious at first unless you’re Dutch. Now is better than never. Although never is often better than right now. If the implementation is hard to explain, it’s a bad idea. If the implementation is easy to explain, it may be a good idea. Namespaces are one honking great idea – let’s do more of those!

Chapter 2 Data Types

001 variables

msg = "hello"
print(msg)

hello

002 string operations

name = "ada lovelace"
print(name.title())
print(name.upper())
print(name.lower())

Ada Lovelace ADA LOVELACE ada lovelace

new_msg = msg + " " + name
print ('\t' + new_msg + '\n')

hello ada lovelace

msg_1 = '     hiuf yeb   w hviu ywe r         '
print(msg_1.rstrip())

 hiuf yeb   w hviu ywe r

msg_1 = msg_1.rstrip()
print(msg_1.lstrip())

hiuf yeb w hviu ywe r

msg_1 = '\t' + msg_1 + '\n'
print(msg_1)
msg_1 = msg_1.rstrip()
print(msg_1)
msg_1 = msg_1.lstrip()
print(msg_1)

	     hiuf yeb   w hviu ywe r

	     hiuf yeb   w hviu ywe r
hiuf yeb   w hviu ywe r

003 number operations

10**6

3/2

1.5

3//2

0.1*3

0.30000000000000004

floats’ problems still exists in python3, but it’s common in any language due to how computers save these floats

004 number&string

num_test_1 = 666
print(num_test_1)
    # print('huvife' + num_test_1 + 'gbtehgbe')
    # error version
print('huvife' + str(num_test_1) + 'gbtehgbe')
    # or
num_test_1 = '666'
print('huvife' + num_test_1 + 'gbtehgbe')

666
huvife666gbtehgbe
huvife666gbtehgbe

Chapter 3 List

There is no array in Python!!!

001 Introduction to Lists

arr = ['vfervewr','gftewgwter','gtewgewwe','gtwgw']
print(arr)
print(arr[0].title())
print(arr[-1]) #see? minus is not only available, but useful!
print(arr[-3])
message = "vfsvegeerwsgetrw " + arr[0] + " vbgfdbgfrdsbg"
print(message)
    # message = "vfsvegeerwsgetrw " + arr + " vbgfdbgfrdsbg"
    # print(message)
    # error version

['vfervewr', 'gftewgwter', 'gtewgewwe', 'gtwgw']
Vfervewr
gtwgw
gftewgwter
vfsvegeerwsgetrw vfervewr vbgfdbgfrdsbg

Again, thers is no array in Python! So don’t follow my mistake! (I used ‘arr’ to name a list, because I thought they were the same!)

002 Modifying Lists

arr[0] = 'cool'
print(arr)

['cool', 'gftewgwter', 'gtewgewwe', 'gtwgw', 'new one', 666]

003 Add Elements

arr.append('new one')
print(arr)

['cool', 'gftewgwter', 'gtewgewwe', 'gtwgw', 'new one', 666, 'new one']

You can even create an empty list and add elements to it later!

motor = []

motor.append('honda')
motor.append('yamaha')
motor.append('suzuki')

print(motor)

['honda', 'yamaha', 'suzuki']

004 Insert Elements

motor.insert(0,'ducati')
print(motor)

['ducati', 'honda', 'yamaha', 'suzuki']

005 Delete Elements

print(motor)

del motor[1]
print(motor)

['ducati', 'honda', 'yamaha', 'suzuki']
['ducati', 'yamaha', 'suzuki']

006 Pop Elements

print(motor)

poped_motor = motor.pop()
print(motor)
print(poped_motor)

['ducati', 'yamaha', 'suzuki']
['ducati', 'yamaha']
suzuki

This way, you can still use the element you want to delete for the last time.
This is useful! Watch this example!

motor = ['ducati', 'honda', 'yamaha', 'suzuki']

last_owned = motor.pop()
print("The last motorcycle I owned was a " + last_owned.title() + ".")
print(motor)

The last motorcycle I owned was a Suzuki.
['ducati', 'honda', 'yamaha']

And pop can be used to pop any element!

motor = ['ducati', 'honda', 'yamaha', 'suzuki']

first_owned = motor.pop(0)
print("The first motorcycle I owned was a " + first_owned.title() + ".")
print(motor)

The first motorcycle I owned was a Ducati.
['honda', 'yamaha', 'suzuki']

007 Remove Elements According to Its Value

motor = ['ducati', 'honda', 'yamaha', 'suzuki']

motor.remove('ducati')
print(motor)

['honda', 'yamaha', 'suzuki']

motor = ['ducati', 'honda', 'yamaha', 'suzuki']

too_expensive = 'ducati'
motor.remove(too_expensive)
print(motor)
print("\nA " + too_expensive.title() + " is too expensive for me.")

['honda', 'yamaha', 'suzuki']

A Ducati is too expensive for me.

008 Arrange Lists

To Sort Permanently

cars = ['bmw', 'audi', 'toyota', 'subaru']
cars.sort()
print(cars)

['audi', 'bmw', 'subaru', 'toyota']

cars = ['bmw', 'audi', 'toyota', 'subaru']
cars.sort(reverse = True)
print(cars)

['toyota', 'subaru', 'bmw', 'audi']

To Sort Temporarily

cars = ['bmw', 'audi', 'toyota', 'subaru']
print(cars)
print(sorted(cars))
print(cars)

['bmw', 'audi', 'toyota', 'subaru']
['audi', 'bmw', 'subaru', 'toyota']
['bmw', 'audi', 'toyota', 'subaru']

To Reverse

cars = ['bmw', 'audi', 'toyota', 'subaru']
print(cars)
cars.reverse() #don't forget the "()"!
print(cars)
cars.reverse()
print(cars)

['bmw', 'audi', 'toyota', 'subaru']
['subaru', 'toyota', 'audi', 'bmw']
['bmw', 'audi', 'toyota', 'subaru']

To Confirm the Length

cars = ['bmw', 'audi', 'toyota', 'subaru']
len(cars)

Chapter 4 Operate the List

001 For: Loop

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
    print(magician.title() + ", that was a great trick!")

Alice, that was a great trick!
David, that was a great trick!
Carolina, that was a great trick!

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
    print(magician.title() + ", that was a great trick!")
    print("I can't wait to see your next trick, " + magician.title() + ".\n")

Alice, that was a great trick!
I can't wait to see your next trick, Alice.

David, that was a great trick!
I can't wait to see your next trick, David.

Carolina, that was a great trick!
I can't wait to see your next trick, Carolina.

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
    print(magician.title() + ", that was a great trick!")
    print("I can't wait to see your next trick, " + magician.title() + ".\n")
print("Thank you, all!")

Alice, that was a great trick!
I can't wait to see your next trick, Alice.

David, that was a great trick!
I can't wait to see your next trick, David.

Carolina, that was a great trick!
I can't wait to see your next trick, Carolina.

Thank you, all!

As you can see, indent is very important in Python. It can decide whether your program will be running properly.

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
print(magician.title() + ", that was a great trick!")

  File "<ipython-input-32-f0b382b2b777>", line 3
    print(magician.title() + ", that was a great trick!")
        ^
IndentationError: expected an indented block

See? An error occured when you don’t indent the code!

msg = "hello"
    print(msg)

Errors also occur when there’s an unnecessary indent!

002 Use A Number As the Loop Control Variable

for value in range(1,6):
    print(value)

range() stops when value reaches 6, which means after 5 is printed and value has been 6, the program will stop.

And range() has other ways to use.

numbers = list(range(1,6))
print(numbers)

odd_numbers = list(range(1,11,2))
print(odd_numbers)

squares = []
for value in range(1,11):
    squares.append(value**2)
print(squares)

digits = list(range(0,10))
min(digits)

max(digits)

sum(digits)

squares = [value**2 for value in range(1,11)]
print(squares)

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print(players[0:3])

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print(players[1:4])

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print(players[:4])

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print(players[2:])

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print(players[-3:])

players = ['charles', 'martina', 'micheal', 'florence', 'eli']
print("Here are the first three players on my team:")
for player in players[:3]:
    print(player.title())

my_foods = ['pizza', 'falafel', 'carrot cake']
friend_foods = my_foods

print("My favorite foods are:")
print(my_foods)

print("\nMyfriend's favorite foods are:")
print(friend_foods)

my_foods = ['pizza', 'falafel', 'carrot cake']
friend_foods = my_foods[:]

print("My favorite foods are:")
print(my_foods)

print("\nMyfriend's favorite foods are:")
print(friend_foods)

my_foods = ['pizza', 'falafel', 'carrot cake']
friend_foods = my_foods[:]

my_foods.append('cannoli')
friend_foods.append('ice cream')

print("My favorite foods are:")
print(my_foods)

print("\nMyfriend's favorite foods are:")
print(friend_foods)

my_foods = ['pizza', 'falafel', 'carrot cake']
friend_foods = my_foods
# Not Workable

my_foods.append('cannoli')
friend_foods.append('ice cream')

print("My favorite foods are:")
print(my_foods)

print("\nMyfriend's favorite foods are:")
print(friend_foods)

Mind the tiny difference between the two codes. Though they look similar, the results are totally different!

dimensions = (200, 50)
print(dimensions[0])
print(dimensions[1])

Edting the elements in a tuple is illegal!

dimensions = (200, 50)
dimensions[0] = 250

dimensions = (200, 50)
for dimension in dimensions:
    print(dimension)

200
50

However, assigning the whole tuple is allowed!

dimensions = (200, 50)
print("origin:")
print(dimensions)

dimensions = (400, 100)
print("modified:")
print(dimensions)

origin:
(200, 50)
modified:
(400, 100)

005 PEP 8

Check Here for more details. https://www.python.org/dev/peps/pep-0008/

Chapter 5 If Statement

001 Simple Example

cars = ['audi', 'bmw', 'subaru', 'toyota']

for car in cars:
    if car == 'bmw':
        print(car.upper())
    else:
        print(car.title())

Audi
BMW
Subaru
Toyota

002 Condition Testing

car = 'bmw'
car == 'bmw'

True

car = 'bmw'
car == 'audi'

False

car = 'Audi'
car == 'audi'

False

car = 'Audi'
car.lower() == 'audi'

True

car = 'Audi'
car.lower() == 'audi'

car

'Audi'

car = 'Audi'
car.lower() == 'auDi'.lower()

True

!= is availiable, too!

str1 = 'hello'
str2 = 'hel'
str1 != str2

True

Numbers are workable, too!

age = 18
age == 18

True

age >= 18

True

age > 17

True

age > 16 and age < 19

True

(age > 16) and (age < 19)

True

(age < 16) or (age != 17)

True

requested_toppings = ['mushrooms', 'onions', 'pineapple']
'mushrooms' in requested_toppings

True

'apple' in requested_toppings

False

bool1 = True
bool2 = False
bool1 and bool2

False

003 If Statement

age = 12

if age < 4:
    print(1)
elif age < 18:
    print(2)
elif age > 65:
    print(3)
else:
    print(4)

age = 1

if age < 4:
    print(1)
elif age < 18:
    print(2)
elif age > 65:
    print(3)

004 Combination

requested_toppings = ['mushrooms', 'green peppers', 'extra cheese']

for requested_topping in requested_toppings:
    if requested_topping == 'green peppers':
        print("Sorry, we ran out of " + requested_topping + ".")
    else:
        print("Adding " + requested_topping + ".")

print("Finished!")

Adding mushrooms.
Sorry, we ran out of green peppers.
Adding extra cheese.
Finished!

requested_toppings = []

if requested_toppings:
    for requested_topping in requested_toppings:
        if requested_topping == 'green peppers':
            print("Sorry, we ran out of " + requested_topping + ".")
        else:
            print("Adding " + requested_topping + ".")
else:
    print("You want a plain pizza?")

You want a plain pizza?

available_toppings = ['mushrooms', 'extra cheese']
requested_toppings = ['mushrooms', 'green peppers', 'extra cheese']

if requested_toppings:
    for requested_topping in requested_toppings:
        if requested_topping in available_toppings:
            print("Adding " + requested_topping + ".")
        else:
            print("Sorry, we ran out of " + requested_topping + ".")
else:
    print("You want a plain pizza?")

print("\nFinished!")

Adding mushrooms.
Sorry, we ran out of green peppers.
Adding extra cheese.

Finished!

Chapter 6 Dictionary

001 A Simple Example

alien_0 = {'color' : 'green', 'points' : 5}

print(alien_0['color'])
print(alien_0['points'])

green
5

A dictionary is a series of “key = value”. In this case, ‘color’ and ‘points’ are two keys, and ‘green’ and 5 are two values.

alien_0 = {'color' : 'green', 'points' : 5}

color_0 = alien_0['color']
print('The color is ' + color_0 + '.')

The color is green.

alien_0 = {'color' : 'green', 'points' : 5}

print('The color is ' + alien_0['color'] + '.')

The color is green.

alien_0 = {'color' : 'green', 'points' : 5}
print(alien_0)

alien_0['x_position'] = 0
alien_0['y_position'] = 25
print(alien_0)

{'color': 'green', 'points': 5}
{'color': 'green', 'points': 5, 'x_position': 0, 'y_position': 25}

You can create an empty dictionary for convenience, just like you have done for lists.

alien_0 = {}
print(alien_0)

alien_0['color'] = 'green'
alien_0['points'] = 5
print(alien_0)

{}
{'color': 'green', 'points': 5}

002 Modification and Deletion

alien_0 = {'color' : 'green', 'points' : 5}
print(alien_0)

alien_0['color'] = 'yellow'
print(alien_0)

{'color': 'green', 'points': 5}
{'color': 'yellow', 'points': 5}

alien_0 = {'color' : 'green', 'points' : 5}
print(alien_0)

del alien_0['points']
print(alien_0)

{'color': 'green', 'points': 5}
{'color': 'green'}

Code Standards For Long Statements

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
}

print("Sarah's favorite language is " + 
     favorite_languages['sarah'].title() + 
     '.')

Sarah's favorite language is C.

003 Traverse A Dictionary

user_0 = {
    'username' : 'efermi',
    'first' : 'enrico',
    'last' : 'fermi',
    }

for key, value in user_0.items():
    print("\nKey: " + key)
    print("Value: " + value)

Key: username
Value: efermi

Key: first
Value: enrico

Key: last
Value: fermi

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

for name, language in favorite_languages.items():
    print(name.title() + "'s favortie language is " +
         language.title() + ".")

Jen's favortie language is Python.
Sarah's favortie language is C.
Edward's favortie language is Ruby.
Phil's favortie language is Python.

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

for name in favorite_languages.keys():
    print(name.title())

Jen
Sarah
Edward
Phil

In fact, .keys() can be omitted.

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

for name in favorite_languages: #mind here!
    print(name.title())

Jen
Sarah
Edward
Phil

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

friends = ['phil', 'sarah']
for name in favorite_languages.keys():
    print(name.title())
    
    if name in friends:
        print(" Hi! " + name.title() + 
              ", I see your favorite language is " +
             favorite_languages[name].title() + "!")

Jen
Sarah
 Hi! Sarah, I see your favorite language is C!
Edward
Phil
 Hi! Phil, I see your favorite language is Python!

This is how .keys() actually works.

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

favorite_languages.keys()

dict_keys(['jen', 'sarah', 'edward', 'phil'])

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

if 'erin' not in favorite_languages.keys():
    print("Erin, please take our poll!")

Erin, please take our poll!

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

for name in sorted(favorite_languages.keys()):
    print(name.title())

Edward
Jen
Phil
Sarah

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

favorite_languages.values()

dict_values(['python', 'C', 'ruby', 'python'])

favorite_languages = {
    'jen' : 'python',
    'sarah' : 'C',
    'edward' : 'ruby',
    'phil' : 'python',
    }

set(favorite_languages.values())

{'C', 'python', 'ruby'}

This will remove the repeated values!

004 Nest

Dictionaries in A List

aliens = []

for alien_number in range(30):
    new_alien = {'color': 'green', 'points': 5, 'speed': 'slow'}
    aliens.append(new_alien)

for alien in aliens[0:3]:
    if alien['color'] == 'green':
        alien['color'] = 'yellow'
        alien['speed'] = 'medium'
        alien['points'] = 10
    elif alien['color'] == 'yellow':
        alien['color'] = 'res'
        alien['speed'] = 'fast'
        alien['points'] = 15
    
for alien in aliens[:5]:
    print(alien)
print("...")

print("Total number of aliens: " + str(len(aliens)))

{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'green', 'points': 5, 'speed': 'slow'}
{'color': 'green', 'points': 5, 'speed': 'slow'}
...
Total number of aliens: 30

Lists in A Dictionary

favorite_languages = {
    'jen' : ['python', 'ruby'],
    'sarah' : ['C'],
    'edward' : ['ruby', 'go'],
    'phil' : ['python', 'haskell'],
    }

for name, language in favorite_languages.items():
    if len(language) == 1:
        print("\n" + name.title() + "'s favorite language is " + language[0].title())
    else:
        print("\n" + name.title() + "'s favorite languages are:")
        for language in languages:
            print("\t" + language.title())

Jen's favorite languages are:
	Python
	Haskell

Sarah's favorite language is C

Edward's favorite languages are:
	Python
	Haskell

Phil's favorite languages are:
	Python
	Haskell

users = {
    'aeinsein' : {
        'first' : 'albert',
        'last' : 'einstein',
        'location' : 'princeton',
        },
    'mcurie':{
        'first' : 'marie',
        'last' : 'curie',
        'location' : 'paris',
        },
    }

for username, user_info in users.items():
    print("\nUsername: " + username)
    full_name = user_info['first'] + " " + user_info['last']
    location = user_info['location']
    
    print("\tFull name:" + full_name.title())
    print("\tLocation: " + location.title())

Username: aeinsein
	Full name:Albert Einstein
	Location: Princeton

Username: mcurie
	Full name:Marie Curie
	Location: Paris

Chapter 7 Input and While Loop

001 `input()` ？ Try `int()`

msg = input("Tell me sth:")
print(msg)

Tell me sth:test
test

msg0 = "hello "
msg0 += "\ninput sth: "

msg1 = input(msg0)
print(msg1)

hello 
input sth: test1
test1

But, how to input a number?

age = input("your age")
age

your age18





'18'

age = input("your age")
age >= 18

your age18



---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-9-74683d3f63a8> in <module>
      1 age = input("your age")
----> 2 age >= 18


TypeError: '>=' not supported between instances of 'str' and 'int'

age1 = input(age1)
age1

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-7-b4864473f466> in <module>
----> 1 age1 = input(age1)
      2 age1


NameError: name 'age1' is not defined

Above is just a silly test out of my curiosity.

age = input("your age")
age = int(age)
age >= 18

your age18





True

Mod `%`

4 % 3

num = input()
num = int(num)

if num % 2 == 0:
    print("\nThe number " + num + " is even.")
else:
    print("\nThe number " + num + " is odd.")

100



---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-13-2b870bf3f31d> in <module>
      3 
      4 if num % 2 == 0:
----> 5     print("\nThe number " + num + " is even.")
      6 else:
      7     print("\nThe number " + num + " is odd.")


TypeError: must be str, not int

num = input()
num = int(num)

if num % 2 == 0:
    print("\nThe number " + str(num) + " is even.")
else:
    print("\nThe number " + str(num) + " is odd.")

100

The number 100 is even.

Bear in mind that str() is necessary when inserting a number into a string.

002 While

cnt = 1
while cnt <= 5:
    print(cnt)
    cnt += 1

cnt++ is illegal in Python!

msg = ""
while msg != "quit":
    msg = input(msg)
    if msg != "quit":
        print(msg + "\n")

666
666

666quit

active = True
while active:
    msg = input()
    if msg == "quit":
        active = False
    else:
        print(msg)

666
666
quit

while True:
    msg = input()
    if msg == "quit":
        break
    else:
        print(msg)

666
666
quit

i = 0
while i < 10:
    i += 1
    if i % 2 == 0:
        continue
    
    print(i)

i = 1
while i < 10:
    print(i)

Above is a endless loop!

003 While & List & Dictionary

unconfirmed_users = ['alice', 'brain', 'candace']
confirmed_users = []

while unconfirmed_users:
    current_user = unconfirmed_users.pop()
    
    print("Verifying user: " + current_user.title())
    confirmed_users.append(current_user)
    
print("\nThe following users have been confirmed:")
for confirmed_user in confirmed_users:
    print(confirmed_user.title())

Verifying user: Candace
Verifying user: Brain
Verifying user: Alice

The following users have been confirmed:
Candace
Brain
Alice

pets = ['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
print(pets)

while 'cat' in pets:
    pets.remove('cat')
    
print(pets)

['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
['dog', 'dog', 'goldfish', 'rabbit']

responses = {}

polling_active = True

while polling_active:
    name = input("\nWhat's your name? ")
    response = input("Which mountain would you like to climb someday? ")
    
    responses[name] = response
    
    repeat = input("Would you like to let another person respond? (yes/no)")
    if repeat == 'no':
        polling_active = False
print("\n--- Poll Results ---")
for name, response in responses.items():
    print(name + " would like to climb " + response + '.')

What's your name? 1
Which mountain would you like to climb someday? 1
Would you like to let another person respond? (yes/no)No

What's your name? 2
Which mountain would you like to climb someday? 2
Would you like to let another person respond? (yes/no)no

--- Poll Results ---
1 would like to climb 1.
2 would like to climb 2.

Chapter 8 Function

001 Define a function

def greet_user():
    print("Hello!")
    
greet_user()

Hello!

def greet_user(username):
    print("Hello, " + username.title() + "!")
    
greet_user("charlie")

Hello, Charlie!

Mind the formal parameter and the actual parameter

def describe_pet(animal_type, pet_name):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet("hamster", 'harry')

I have a hamster.
My hamster's name isHarry.

def describe_pet(animal_type, pet_name):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet("hamster", 'harry')
describe_pet("dog", 'willie')

I have a hamster.
My hamster's name isHarry.

I have a dog.
My dog's name isWillie.

def describe_pet(animal_type, pet_name):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet("hamster", 'harry')
describe_pet('harry', "hamster")
describe_pet(animal_type = 'hamster', pet_name = 'harry')
describe_pet(pet_name = 'harry', animal_type = 'hamster')

I have a hamster.
My hamster's name isHarry.

I have a harry.
My harry's name isHamster.

I have a hamster.
My hamster's name isHarry.

I have a hamster.
My hamster's name isHarry.

Mind the last two calling of the function describe_pet !

002 Functions with default values

def describe_pet(pet_name, animal_type = 'dog'):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet('harry', "hamster")
describe_pet('willie')

I have a hamster.
My hamster's name isHarry.

I have a dog.
My dog's name isWillie.

def describe_pet(animal_type = 'dog', pet_name):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet("hamster", 'harry')
describe_pet('willie')

  File "<ipython-input-22-783719293d54>", line 1
    def describe_pet(animal_type = 'dog', pet_name):
                    ^
SyntaxError: non-default argument follows default argument

This time, an error occured!

def describe_pet(animal_type = 'dog', pet_name):
    print("\nI have a " + animal_type + ".")
    print("My " + animal_type + "'s name is" + pet_name.title() + ".")
    
describe_pet("hamster", 'harry')
describe_pet(pet_name = 'willie')

  File "<ipython-input-23-697809b5a3b4>", line 1
    def describe_pet(animal_type = 'dog', pet_name):
                    ^
SyntaxError: non-default argument follows default argument

Another error!

In Python, you have to put the non-default arguments before the default ones!!!

003 Return Value

def get_full_name(first_name, second_name):
    full_name = first_name + ' ' + second_name
    return full_name.title()

musician = get_full_name('jimi', 'hendrix')
print(musician)

Jimi Hendrix

def get_formatted_name(first_name, last_name, middle_name=''): # Pay Attention!
    if middle_name:
        full_name = first_name + ' ' + middle_name + ' ' + last_name
    else:
        full_name = first_name + ' ' + last_name
    return full_name.title()

musician = get_formatted_name('jimi', 'hendrix')
print(musician)

musician = get_formatted_name('john', 'hooker', 'lee')
print(musician)

Jimi Hendrix
John Lee Hooker

def build_person(first_name, last_name, age=''):
    person = {'first': first_name, 'last': last_name}
    if age:
        person['age'] = age
    return person

musician = build_person('jimi', 'hendrix')
print(musician)

musician = build_person('jimi', 'hendrix', 27)
print(musician)

{'first': 'jimi', 'last': 'hendrix'}
{'first': 'jimi', 'last': 'hendrix', 'age': 27}

def get_full_name(first_name, second_name):
    full_name = first_name + ' ' + second_name
    return full_name.title()

while True:
    print("\nPlease tell me your name:")
    print("(Enter 'q' to quit!)")
    f_name = input("First name:")
    if f_name == 'q':
        break;
    l_name = input("Last name:")
    if l_name == 'q':
        break;
    
    formatted_name = get_full_name(f_name, l_name)
    print("\nHello, " + formatted_name + '!')

Please tell me your name:
(Enter 'q' to quit!)
First name:charlie
Last name:jiang

Hello, Charlie Jiang!

Please tell me your name:
(Enter 'q' to quit!)
First name:charlie
Last name:jiang

Hello, Charlie Jiang!

Please tell me your name:
(Enter 'q' to quit!)
First name:c
Last name:q

004 Relay Lists

def greet_users(names):
    for name in names:
        msg = "Hello, " + name.title() + "!"
        print(msg)
        
usernames = ['hannah', 'ty', 'margot']
greet_users(usernames)

Hello, Hannah!
Hello, Ty!
Hello, Margot!

def print_models(unprinted_designs, completed_models):
    while unprinted_designs:
        current_design = unprinted_designs.pop()
        print("Printing: " + current_design)
        completed_models.append(current_design)
        
def show_completed_models(completed_models):
    print("\nThe following models have been printed:")
    for completed_model in completed_models:
        print(completed_model)
        
unprinted_designs = ['iphone case', 'robot pendant', 'dodecahedron']
completed_models = []

print_models(unprinted_designs, completed_models)
show_completed_models(completed_models)

print(unprinted_designs)

Printing: dodecahedron
Printing: robot pendant
Printing: iphone case

The following models have been printed:
dodecahedron
robot pendant
iphone case
[]

def print_models(unprinted_designs, completed_models):
    while unprinted_designs:
        current_design = unprinted_designs.pop()
        print("Printing: " + current_design)
        completed_models.append(current_design)
        
def show_completed_models(completed_models):
    print("\nThe following models have been printed:")
    for completed_model in completed_models:
        print(completed_model)
        
unprinted_designs = ['iphone case', 'robot pendant', 'dodecahedron']
completed_models = []

print_models(unprinted_designs[:], completed_models)
show_completed_models(completed_models)

print(unprinted_designs)

Printing: dodecahedron
Printing: robot pendant
Printing: iphone case

The following models have been printed:
dodecahedron
robot pendant
iphone case
['iphone case', 'robot pendant', 'dodecahedron']

The second version of this programme conveys a copy of a list!

005 Relay as many actual parameters as you like!

def make_pizza(*toppings):
    print("\nMaking a pizza with the following toppings:")
    for topping in toppings:
        print("- " + topping)
        
make_pizza('pepperoni')
make_pizza('mushrooms', 'green peppers', 'extra cheese')

Making a pizza with the following toppings:
- pepperoni

Making a pizza with the following toppings:
- mushrooms
- green peppers
- extra cheese

* let Python create a tuple that contains the actual parameters you relayed, no matter how many actual parameters you relayed to the function.

def make_pizza(size, *toppings):
    print("\nMaking a " + str(size) + "-inch pizza with the following toppings:")
    for topping in toppings:
        print("- " + topping)
        
make_pizza(16, 'pepperoni')
make_pizza(12, 'mushrooms', 'green peppers', 'extra cheese')

Making a 16-inch pizza with the following toppings:
- pepperoni

Making a 12-inch pizza with the following toppings:
- mushrooms
- green peppers
- extra cheese

def build_profile(first, last, **user_info):
    profile = {}
    profile['first_name'] = first
    profile['last_name'] = last
    for key,value in user_info.items():
        profile[key] = value
    return profile

user_profile = build_profile('albert', 'einstein', 
                            location = 'princeton',
                            field = 'physics')
print(user_profile)

{'first_name': 'albert', 'last_name': 'einstein', 'location': 'princeton', 'field': 'physics'}

** let Python create a dictionary that contains the keys and values you relayed, no matter how many pairs you have relayed to the function.

006 Import

Due to the difficulty of using import in notebook. I’ll practice this part in sublime text 3.

007 PEP8, again!

def function_name(parameter_0, parameter_1='default_value')

function_name(value_0, parameter_1='value_1')

def function_name(
        parameter_0, parameter_1, parameter_2,
        parameter_3, parameter_4, parameter_5):
    function body...

Chapter 9 Class

001 Introduction to Class

class Dog():
    def __init__(self, name, age):
        self.name = name
        self.age = age
        
    def sit(self):
        print(self.name.title() + " is now sitting.")
        
    def roll_over(self):
        print(self.name.title() + " rolled over!")
        
my_dog = Dog('willie', 6)

print("name: " + my_dog.name.title())
print("age: " + str(my_dog.age))

name: Willie
age: 6

my_dog = Dog('willie', 6)

print("name: " + my_dog.name.title())
print("age: " + str(my_dog.age))

name: Willie
age: 6

Mind that __init__ has two _s at each side!

my_dog.sit()

Willie is now sitting.

my_dog.roll_over()

Willie rolled over!

your_dog = Dog('Lucy', 3)

your_dog.name

'Lucy'

your_dog.age

your_dog.sit()

Lucy is now sitting.

002 Use Class and Instances

class Car():
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
        
    def get_descriptive_name(self):
        long_name = str(self.year) + " " + self.make + " " + self.model
        return long_name.title()
    
    def read_odometer(self):
        print("This car has " + str(self.odometer_reading) + " miles on it.")
    
my_new_car = Car('audi', 'a4', 2016)
print(my_new_car.get_descriptive_name())
my_new_car.read_odometer()

2016 Audi A4
This car has 0 miles on it.

Here are some ways to change properties.

my_new_car.odometer_reading = 23
my_new_car.read_odometer()

This car has 23 miles on it.

class Car():
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
        
    def get_descriptive_name(self):
        long_name = str(self.year) + " " + self.make + " " + self.model
        return long_name.title()
    
    def read_odometer(self):
        print("This car has " + str(self.odometer_reading) + " miles on it.")
    
    def update_odometer(self, mileage):
        if mileage > self.odometer_reading:
            self.odometer_reading = mileage
        else:
            print("You can't roll back an odometer!")
    
my_new_car = Car('audi', 'a4', 2016)
print(my_new_car.get_descriptive_name())
my_new_car.read_odometer()
my_new_car.update_odometer(23)
my_new_car.read_odometer()

2016 Audi A4
This car has 0 miles on it.
This car has 23 miles on it.

my_new_car.update_odometer(46)
my_new_car.read_odometer()
my_new_car.update_odometer(23)
my_new_car.read_odometer()

This car has 46 miles on it.
You can't roll back an odometer!
This car has 46 miles on it.

class Car():
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
        
    def get_descriptive_name(self):
        long_name = str(self.year) + " " + self.make + " " + self.model
        return long_name.title()
    
    def read_odometer(self):
        print("This car has " + str(self.odometer_reading) + " miles on it.")
    
    def update_odometer(self, mileage):
        if mileage > self.odometer_reading:
            self.odometer_reading = mileage
        else:
            print("You can't roll back an odometer!")
            
    def increment_odometer(self, miles):
        if miles > 0:
            self.odometer_reading += miles
        else:
            print("You can't roll back an odometer!")
    
my_new_car = Car('audi', 'a4', 2016)
print(my_new_car.get_descriptive_name())
my_new_car.read_odometer()
my_new_car.update_odometer(23)
my_new_car.read_odometer()
my_new_car.increment_odometer(100)
my_new_car.read_odometer()
my_new_car.increment_odometer(-100)
my_new_car.read_odometer()

2016 Audi A4
This car has 0 miles on it.
This car has 23 miles on it.
This car has 123 miles on it.
You can't roll back an odometer!
This car has 123 miles on it.

003 Inheritance

class Car():
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
        
    def get_descriptive_name(self):
        long_name = str(self.year) + " " + self.make + " " + self.model
        return long_name.title()
    
    def read_odometer(self):
        print("This car has " + str(self.odometer_reading) + " miles on it.")
    
    def update_odometer(self, mileage):
        if mileage > self.odometer_reading:
            self.odometer_reading = mileage
        else:
            print("You can't roll back an odometer!")
            
    def increment_odometer(self, miles):
        if miles > 0:
            self.odometer_reading += miles
        else:
            print("You can't roll back an odometer!")
            
    def fill_gas_tank(self):
        print("Filled!")
    
class ElectricCar(Car):
    def __init__(self, make, model, year):
        super().__init__(make, model, year)
        self.battery_size = 70
    
    def describe_battery(self):
        print("This car has a " + str(self.battery_size) + "-kWh battery.")
        
    def fill_gas_tank(self):
        print("This car doesn't need a gas tank!")
        
my_tesla = ElectricCar('tesla', 'model s', 2016)
print(my_tesla.get_descriptive_name())
my_tesla.describe_battery()
my_tesla.fill_gas_tank()

2016 Tesla Model S
This car has a 70-kWh battery.
This car doesn't need a gas tank!

Don’t forget self !!!

class Car():
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
        
    def get_descriptive_name(self):
        long_name = str(self.year) + " " + self.make + " " + self.model
        return long_name.title()
    
    def read_odometer(self):
        print("This car has " + str(self.odometer_reading) + " miles on it.")
    
    def update_odometer(self, mileage):
        if mileage > self.odometer_reading:
            self.odometer_reading = mileage
        else:
            print("You can't roll back an odometer!")
            
    def increment_odometer(self, miles):
        if miles > 0:
            self.odometer_reading += miles
        else:
            print("You can't roll back an odometer!")
            
    def fill_gas_tank(self):
        print("Filled!")
    
class Battery():
    def __init__(self, battery_size=70):
        self.battery_size = battery_size
        
    def describe_battery(self):
        print("This car has a " + str(self.battery_size) + "-kWh battery.")
        
    def get_range(self):
        if self.battery_size == 70:
            range = 240
        elif self.battery_size == 85:
            range = 270
            
        message = "This car can go approximately " + str(range)
        message += " miles on a full charge."
        print(message)
    
class ElectricCar(Car):
    def __init__(self, make, model, year):
        super().__init__(make, model, year)
        self.battery = Battery()
        
    def fill_gas_tank(self):
        print("This car doesn't need a gas tank!")
        
my_tesla = ElectricCar('tesla', 'model s', 2016)
print(my_tesla.get_descriptive_name())

my_tesla.battery.describe_battery()
my_tesla.battery.get_range()

2016 Tesla Model S
This car has a 70-kWh battery.
This car can go approximately 240 miles on a full charge.

004 Import Class

Similar to import functions.

005 Python Standard Library

from collections import OrderedDict

favorite_languages = OrderedDict()

favorite_languages['jen'] = 'python'
favorite_languages['sarah'] = 'c'
favorite_languages['edward'] = 'ruby'
favorite_languages['phil'] = 'python'

for name, language in favorite_languages.items():
    print(name.title() + "'s favorite language is " +
         language.title() + ".")

Jen's favorite language is Python.
Sarah's favorite language is C.
Edward's favorite language is Ruby.
Phil's favorite language is Python.

Chapter 1 Setup#

Chapter 2 Data Types#

001 variables#

002 string operations#

003 number operations#

004 number&string#

Chapter 3 List#

001 Introduction to Lists#

002 Modifying Lists#

003 Add Elements#

004 Insert Elements#

005 Delete Elements#

006 Pop Elements#

007 Remove Elements According to Its Value#

008 Arrange Lists#

Chapter 4 Operate the List#

001 For: Loop#

002 Use A Number As the Loop Control Variable#

005 PEP 8#

Chapter 5 If Statement#

001 Simple Example#

002 Condition Testing#

003 If Statement#

004 Combination#

Chapter 6 Dictionary#

001 A Simple Example#

002 Modification and Deletion#

003 Traverse A Dictionary#

004 Nest#

Dictionaries in A List#

Lists in A Dictionary#

Chapter 7 Input and While Loop#

001 input() ？ Try int()#

Mod %#

002 While#

003 While & List & Dictionary#

Chapter 8 Function#

001 Define a function#

002 Functions with default values#

003 Return Value#

004 Relay Lists#

005 Relay as many actual parameters as you like!#

006 Import#

007 PEP8, again!#

Chapter 9 Class#

001 Introduction to Class#

002 Use Class and Instances#

003 Inheritance#

004 Import Class#

005 Python Standard Library#