Python Fundamentals - Basic 給新手的 Python 程式設計 | WeiYuan

1. Python Fundamentals - Basic
給新⼿的 Python 程式設計 | WeiYuan

2. site: v123582.github.io
line: weiwei63
▪ 全端⼯程師 + 資料科學家
略懂⼀點網站前後端開發技術，學過資料探勘與機器
學習的⽪⽑。平時熱愛參與技術社群聚會及貢獻開源
程式的樂趣。

3. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
3

4. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
4

5. Introduction
▪The Zen of Python: Beautiful, Explicit, Simple
▪High-level and Interpreted programming language
▪Python 2.x or Python 3.x ?
▪Environment: `python --version`
▪Runtime： shell, command, jupyter/ipython, anaconda
▪Editor/IDE: sublime text, pycharm, spider(built in anaconda)
▪PIP: library manager of python
▪pyenv
5

6. 6

7. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
7

8. Hello World
▪Encoding Declaration
▪Import Library
▪Variable and Assignment
▪Syntax
▪Indentation and Block
▪Input and Output (I/O)
▪Comment and Docstring
▪Function and Method
▪Expression and Operation
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# encoding: utf-8
import this
from keyword import kwlist
# ['False', 'None' . . .]
keywords = kwlist
if len(keywords) > 0:
print(keywords)
x = input("Input Something...")
print("%s", % (x))
help(print)

9. Hello World
▪Case Sensitivity
▪Weekly/Loosely Typed
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# encoding: utf-8
import this
from keyword import kwlist
# ['False', 'None' . . .]
keywords = kwlist
if len(keywords) > 0:
print(keywords)
x = input("Input Something...")
print("%s", % (x))
help(print)

10. Outline
▪Introduction
▪HelloWorld
▪Data Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
10

11. Common Types & Operator
▪Numeric type
• int, float, bool
• abs(), round()
▪String type
▪Container type
• list, tuple, dict, set
11

12. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• abs(), round() => operator + operand
▪String type
▪Container type
• list, tuple, dict, set
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▪expression = operator + operand (varibles)
• arithmetic, comparison

13. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• abs(), round()
▪String type
▪Container type
• list, tuple, dict, set
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▪expression = operator + operand (varibles)
• arithmetic, comparison
arithmetic
comparison
logical
bitwise

14. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• abs(), round()
▪String type
▪Container type
• list, tuple, dict, set
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a = 20
a, b, c, d = 20, 5.5, True, 4+3j
print(type(a)) # <class 'int'>
print(type(b)) # <class 'float'>
print(type(c)) # <class 'bool'>
print(type(d)) # <class 'complex'>
print(isinstance(a, int)) # True
print(isinstance(b, int)) # False
# True, False

15. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• abs(), round()
▪String type
▪Container type
• list, tuple, dict, set
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4 + 2
4.0 + 2
4.0 + 2.0
2 / 5
2.0 / 5
2 / 5.0
2.0 / 5.0
2 // 5
2 % 5
int(4.0)
float(4)

16. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• abs(), round()
▪String type
▪Container type
• list, tuple, dict, set
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# python2
w = 49
h = 163
bmi = 49 / (163/100)**2
print(bmi) # 49
# python3
w = 49.0
h = 163.0
bmi = 49 / (163/100)**2
print(bmi) # 18.4425...

17. Try it!
▪#練習：Set the following variables to the corresponding values:
1. my_int to the value 7
2. my_float to the value 1.23
3. my_bool to the value True
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18. Try it!
▪#練習：計算下列運算：
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1 + 3*2 # 7
1 + 3**2 # 10
(1 + 3)*2 # 8
1 + 3 / 2 *2 # 1
1 + 3 // 2 *2 # 1
1 + 3 / 2 **2 # 1
1 + 3 // 2 **2 # 1
int(1 + 3 / 2 *2) # 1
flaot(1 + 3 // 2 **2) # 1.0

19. Try it!
▪#練習：Add two Numbers
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a = input()
b = input()
…
print('The sum of ‘, a, ‘and’ ,b ,’is’, a + b)

20. Try it!
▪#練習：Add two Numbers
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a = input()
b = input()
…
print('The sum of ‘, a + b, ‘and’ ,a ,’is’, b)
print('The sum of %s and %s is %s ' % (a, b, sum))
print('The sum of {0} and {1} is {2} '.format(a, b, sum))
sum = int(a) + int(b)
print(f'The sum of {a} and {b} is {sum}')

21. Try it!
▪#練習：Find the Square Root
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num = 9
num_sqrt = 3
print('The square root of %0.3f is %0.3f' % (num ,num_sqrt))

22. Common Types & Operator
▪Numeric type
• int, float, bool, complex
▪String type
• len()
• lower(), upper()
• split(), find(), replace()
• slice
• Formatting String
▪Container type
• list, tuple, dict, set
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a = '12345'
b = 'hello world'
c = 'n'
d = r'n'
e = 'n'
print(b + str(a) + c + d + e)
print(b + str(a) + str(c) + str(d) +
str(e))

23. ▪Question：What is different among True, ‘True’, true ?
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24. Try it!
▪#練習：Write a Python program to find the first appearance of
the substring 'not' and 'poor' from a given string, if 'bad' follows
the 'poor', replace the whole 'not'...'poor' substring with 'good'.
Return the resulting string.
• Sample Input: The lyrics is not that poor!
• Sample Output: The lyrics is good!
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25. Try it!
▪#練習：⼀個網址的結構⼤概如圖所⽰，試著⽤ Python 分別把每
個值取出來。
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26. Formatting String
▪Numeric type
• int, float, bool, complex
▪String type
• len(), lower(), upper(), split()
• Formatting String
▪Container type
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a, b, sum = 2, 3, 5
'%s + %s = %s ' % (a, b, sum)
'{} + {} = {} '.format(a, b, sum)
'{x} + {y} = {z} '.format(x=a, y=b,
z=sum)
f'The sum of {a} and {b} is {sum}'

27. Formatting String
▪Numeric type
• int, float, bool, complex
▪String type
• len(), lower(), upper(), split()
• Formatting String
▪Container type
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a, b, sum = 2, 3, 5
'%s + %s = %s ' % (a, b, sum)
'%d + %d = %d ' % (a, b, sum)
'%f + %f = %f ' % (a, b, sum)

28. Formatting String
▪Numeric type
• int, float, bool, complex
▪String type
• len(), lower(), upper(), split()
• Formatting String
▪Container type
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a, b, c = ‘x’, ‘y’, ‘z’
'%s, %s, %s ' % (a, b, c)
'%d, %d, %d ' % (a, b, c)
'%f, %f, %f ' % (a, b, c)

29. Formatting String
▪Numeric type
• int, float, bool, complex
▪String type
• len(), lower(), upper(), split()
• Formatting String
▪Container type
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a, b, sum = 20.12, 30.123, 50.243
'%s + %s = %s ' % (a, b, sum)
'%5d + %6d = %7d ' % (a, b, sum)
'%5.1f + %6.2f = %8.3f ' % (a, b,
sum)

30. Formatting String
▪Numeric type
• int, float, bool, complex
▪String type
• len(), lower(), upper(), split()
• Formatting String
▪Container type
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%s => string
%d => decimal
%f => float
n => new line
t => tab

31. ▪Question：What is Formatting String?
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32. Common Types & Operator
▪Numeric type
• int, float, bool, complex
▪String type
▪Container type
• list [,] => mutable sequence # a = [1, 2, 3, 4], a[0] = 999
• tuple (,) => immutable sequence # b = (1, 2), b[0] = 999
• dict {:,} => mutable unordered collection of key-value mapped element
• set {,} => mutable unordered collections of unique elements
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33. list
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L = [1, 2, 3, 4]
G = [3, 4, 5, 6]
L + G # [1, 2, 3, 4, 3, 4, 5, 6]
L – G # 不存在
L * 2 # [1, 2, 3, 4, 1, 2, 3, 4]
L / 2 # 不存在

34. ▪Question：How does arithmetical operation with string?
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35. list
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my_list = [2] # [2]
my_list.append(2) # [2, 2]
my_list.extend([2]) # [2, 2, 2]
my_list.insert(0, 3) # [3, 2, 2, 2]
my_list.pop() # [3, 2, 2]
my_list.remove(2) # [3, 2]
my_list.sort() # [2, 3]
my_list.reverse() # [3, 2]
my_list[::-1] # [2, 3]
len(my_list) # 2
sum(my_list) # 5
my_list.count(2) # 1
', '.join(my_list) # '2, 3'

36. Try it!
▪#練習：有⼀一個列列表，其中包括 10 個元素，例例如這個列列表是 [1,
2, 3, 4, 5, 6, 7, 8, 9, 0]，要求將最右邊的 0 移到最左邊，結果會
變成 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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37. Try it!
▪#練習：有⼀一個列列表，其中包括 10 個元素，例例如這個列列表是 [1,
2, 3, 4, 5, 6, 7, 8, 9, 0]，要求將最左邊的 1 移到最右邊，結果會
變成 [2, 3, 4, 5, 6, 7, 8, 9, 0, 1]
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38. Try it!
▪#練習：Write a Python program to replace the last element in a
list with another list.
• Sample Input: num1 = [1, 3, 5, 7, 9, 10], num2 = [2, 4, 6, 8]
• Sample Output: [1, 3, 5, 7, 9, 2, 4, 6, 8]
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39. tuple
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(a, b) = my_list
(a, b) = (b, a)

40. Try it!
▪#練習：Swap Two Variables
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41. dict
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my_dict = {'Mark': 1, 'test': 0}
print(my_dict[’Mark’]) # 1
print(my_dict[0])
my_dict['Mary'] = 2 # {'Mark': 1, 'test': 0, ‘Mary’: 2}
del my_dict['test']
my_dict.items()
# dict_items([('Mark', 1), ('Mary', 2) ])
my_dict.keys()
# dict_keys(['Mark', 'Mary'])
my_dict.values()
# dict_values([1, 2])

42. dict
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my_dict['Tom']
# Traceback (most recent call last):
# File "<stdin>", line 1, in <module>
# KeyError: 'openhome’
my_dict.get('Tom', ''), my_dict
# '', {'Mark': 1, 'test': 0}
my_dict.setdefault('Tom', 3), my_dict
# 3, {'Tom': 3, 'Mark': 1, 'test': 0}

43. Try it!
▪#練習：Write a Python program to concatenate following
dictionaries to create a new one.
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# Input:
dic1={1:10, 2:20}
dic2={3:30, 4:40}
dic3={5:50, 6:60}
# Output: {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60}

44. Try it!
▪#練習：Write a Python program to check if a given key already
exists in a dictionary.
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# Input:
d = {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60}
key = input()
# Output: Yes, the key is in this dict. or
# No, the key is not in this dict.

45. set
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admins = {'admin'}
users = {'admin', 'user1', 'user2'}
'Justin' in admins # False
admins & users # {'admin'}
admins | users # {'admin', 'user1', 'user2'}
admins - users # {}
users – admins # {‘user1’, ‘user2’}
admins ^ users # {user1, user2}

46. Try it!
▪#練習：Illustrate Different Set Operations
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# define three sets
E, N = {0, 2, 4, 6, 8}, {1, 2, 3, 4, 5}
print("Intersection of E and N is", E & N) # 2, 4
print("Union of E and N is",E | N) # 0 1 2 3 4 5 6 8
print("Difference of E and N is",E - N) # 1 3 5
print("Symmetric difference of E and N is",E ^ N) # 0 1 3 5
6 8

47. Try it!
▪#練習：Remove the repeated elements from the list, and sort it
Decreasingly.
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l = [1, 1, 3, 9, 7, 8, 8, 8]
# Output: [9, 8, 7, 3, 1]

48. 48
▪Mutable objects
• list, dict, set
▪Immutable objects
• int, float, complex, string, tuple
Reference: https://www.linkedin.com/pulse/mutable-vs-immutable-objects-python-megha-mohan
Im vs Mutable ?

49. 49Reference: https://www.linkedin.com/pulse/mutable-vs-immutable-objects-python-megha-mohan

50. tuple vs list？
▪slower but more powerful than tuples.
▪Lists can be modified, and they have lots of handy operations
we can perform on them.
▪Tuples are immutable and have fewer features.
▪To convert between tuples and lists use the list() and tuple()
functions:
• li = list(tu)
• tu = tuple(li)
50

51. iterator, iterable, iteration
51Reference: http://nvie.com/posts/iterators-vs-generators/

52. iterator, iterable, iteration
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list = [1, 2, 3]
iterator = iter(list)
import sys
sys.getsizeof(list)
sys.getsizeof(iterator)
for i in list:
print(i)
for i in iterator:
print(i)
print(next(iterator))

53. iterator, iterable, iteration
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def f():
i = 1
return i
def g():
i = 1
yield i
i = 2
yield i
a = f()
b = g()
print(a)
print(next(b))

54. bulit-in method
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dir(list)
# ['append', 'clear', 'copy', 'count', 'extend',
'index',# 'insert', 'pop', 'remove', 'reverse', 'sort']
help(list.extend)
# extend(...)
# L.extend(iterable) -> None
# extend list by appending elements from the iterable
Reference: https://docs.python.org/3/library/functions.html

55. Try it!
▪#練習：要求使⽤者輸⼊ n ，印出從 n 平⽅的對數值（Log）
• hint：引入⼀一個 math 的函式庫，並且利利⽤用 dir 與 math 查看 log 函式怎
麼使⽤用
55

56. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
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57. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
57

58. Common Types & Operator
▪Numeric type
• int, float, bool, complex
• expression => operator + operand
▪String type
▪Container type
• list, tuple, dict, set
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▪expression = operator + operand (varibles)
• arithmetic, comparison
arithmetic
comparison
logical
bitwise

59. Flow Control
▪Logical Operator
▪Comparison Operator
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3 is 2, 3 is not 2
True and False, True or False
3 in [1, 2, 3, 4]
1 2 > 2, 2 >= 2, 2 == 2, 2 != 2

60. Flow Control
▪Logical Operator => return Boolean
▪Comparison Operator => return Boolean
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3 is 2, 3 is not 2
True and False, True or False
3 in [1, 2, 3, 4]
1 2 > 2, 2 >= 2, 2 == 2, 2 != 2

61. What it truth?
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62. What it truth?
62

63. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
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if condition:
...
elif condition:
...
else:
...
a = ... if condition else ...

64. 64Reference: http://swcarpentry.github.io/training-course/2013/03/concept-map-conditional-statements-
▪operator
• boolean/logical
• comparison

65. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
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while condition:
....

66. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
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for i in [...]:
...
a = [i for i in [...]] # list
b = (i for i in [...]) # generator

67. Try it!
▪#練習：有⼀一個列列表，其中包括 10 個元素，例例如這個列列表是 [1,
2, 3, 4, 5, 6, 7, 8, 9, 0],要求將列列表中的每個元素⼀一次向前移動⼀一
個位置，第⼀一個元素到列列表的最後，然後輸出這個列列表。最終樣
式是 [2, 3, 4, 5, 6, 7, 8, 9, 0, 1]，如果要把偶數放前⾯，奇數放後
⾯該怎麼做？結果像是 [0, 2, 4, 6, 8, 1, 3, 5, 7, 9]
67

68. Try it!
▪#練習：在數學中，⽤用 n! 來來表⽰示階乘，例例如，4! =1×2×3×4
=24。請寫⼀一個程式，讓使⽤用者輸入 n，印出 n!
1. ⽤用 for 迴圈完成
2. ⽤用 while 迴圈完成
68

69. Try it!
▪#練習：如果將⼀句話作為⼀個字符串，那麼這個字符串中必然
會有空格（這裡只是討論英⽂），⽐如“How are you?”，但有
的時候，會在兩個單詞之間多⼤⼀個空格。現在的任務是，如果
⼀個字符串中有連續的兩個空格，請把它刪除。
69

70. Try it!
▪#練習："Please count the character here."
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# {'r': 3, 'c': 3, 't': 3, ' ': 4, 'n': 1, 'u': 1, 'h': 3,
'e': 6, 'l': 1, 'o': 1, 'a': 3, 's': 1, 'P': 1, '.': 1}

71. Try it!
▪#練習："Here are UPPERCASE and lowercase chars."
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# {'c': ['c', 'c'], 'R': ['R'], 'w': ['w'], ' ': [' ', ' ',
' ', ' ', ' '], '.': ['.'], 'n': ['n'], 'H': ['H'], 'P':
['P', 'P'], 'h': ['h'], 'S': ['S'], 'e': ['e', 'e', 'e',
'e', 'e'], 'l': ['l'], 'E': ['E', 'E'], 'U': ['U'], 'a':
['a', 'a', 'a', 'a'], 'A': ['A'], 'o': ['o'], 'C': ['C'],
'r': ['r', 'r', 'r', 'r'], 'd': ['d'], 's': ['s', 's']}

72. Try it!
▪#練習：畫各種三⾓形與變形
72
*
**
***
****
*
**
***
****
*
***
*****
*******
*
***
*****
*******
*********
*******
*****
***
*

73. ▪https://leetcode.com/problems/two-sum/description/
73

74. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
74

75. Flow Control
▪if - elif - else
▪while
▪for in
▪break, continue
▪range(), zip(), enumerate()
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for i in range(1, 3):
print(i)
for i, j in zip([a, b, c], [1, 2, 3]):
print(i, j)
for i,j in enumerate([a, b, c]):
print(i, j)

76. More zip() …
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result1 = [2, 4, 6, 8]
result2 = [11, 13, 15, 17]
for i, j in zip(result1, result2)
print(i + j)
# 2 11
# 4 13
# 6 15
# 8 17

77. More zip() …
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result3 = [(2, 11), (4, 13), (6, 15), (8, 17)]
for i in zip(*result3):
print(i)
# (2, 4, 6, 8)
# (11, 13, 15, 17)
for i in map(list,zip(*result3)):
print(i)
# [2, 4, 6, 8]
# [11, 13, 15, 17]

78. Try it!
▪#練習：建⽴⼀個 1 - 10 平⽅的數列。
78

79. Try it!
▪#練習：有兩個列表，分別是：a = [1,2,3,4,5]，b = [9,8,7,6,5]，
要計算這兩個列表中對應元素的和。
79

80. Try it!
▪#練習：有⼀個字典 ，myinfor =
{"name":"qiwsir","site":"qiwsir.github.io","lang":"python"}, 將這
個字典變換成 ：infor =
{"qiwsir":"name","qiwsir.github.io":"site","python":"lang"}
80

81. Try it!
▪#練習：按照下⾯的要求實現對列表的操作，產⽣⼀個列表，其
中有40個元素，每個元素是0到100的⼀個隨機整數如果這個列表
中的數據代表著某個班級40⼈的分數，請計算成績低於平均分的
學⽣⼈數，並輸出對上⾯的列表元素從⼤到⼩排序
81

82. Try it!
▪#練習：承上題，想要對分數進⾏調整，不及格的⼈將原始分數
開根號乘以⼗（但最⾼不可以超過 60 分），及格者不變。
82

83. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
83

84. Function
84
1
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4
5
6
7
8
9
max1 = a if a > b else b...
max2 = x if x > y else y...
a = 123
b = 234
// declare funcetion
def max(a, b):
return a if a > b else b
// call function
max(10, 20)
maximum = max
maximum(10, 20)
# 20

85. Basic Method for Call Function
85
1
2
3
4
5
6
7
def f(x=100, y=200):
return x, y
f(1, 2)
f(y=2, x=1)
f(*(1, 2))
f(**{y=2, x=1})

86. Try it!
▪#練習：寫⼀個計算平⽅的函式。
86

87. Try it!
▪#練習：寫⼀個計算平⽅根的函式。
87

88. Try it!
▪#練習：寫⼀個回傳⼀次⽅，⼆次⽅，…，到指定次⽅的函式。
88

89. *args
89
1
2
3
4
5
6
7
8
9
10
def foo(*args):
print(args)
foo(1,2,3) # (1, 2, 3)
foo("qiwsir","qiwsir.github.io","python")
# ('qiwsir', 'qiwsir.github.io', 'python')
foo("qiwsir",307,["qiwsir",2],{"name":"qiwsir"})
# ('qiwsir', 307, ['qiwsir', 2], {'lang': 'python'})

90. **kargs
90
1
2
3
4
5
def foo(**kargs):
print(kargs)
foo(a=1,b=2,c=3)
# {'a': 1, 'c': 3, 'b': 2}

91. type1 + type2 + type3
91
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
def foo(x,y,z,*args,**kargs):
print(x)
print(y)
print(z)
print(args)
print(kargs)
foo('qiwsir',2,"python")
# qiwsir# 2 # python# ()# {}
foo(1,2,3,4,5)
# 1# 2# 3# (4, 5)# {}
foo(1,2,3,4,5,name="qiwsir")
# 1# 2# 3# (4, 5)# {'name': 'qiwsir'}

92. 92Reference: http://swcarpentry.github.io/training-course/2013/05/concept-map-python-functions/

93. Try it!
▪#練習：以下程式會如何輸出？
93
1
2
3
4
5
6
7
8
9
10
11
12
def foo(x,y=‘hello’,*targs,**dargs):
print "x==>",x
print "y==>",y
print "targs_tuple==>",targs
print "dargs_dict==>",dargs
foo("1x")
foo("1x","2y")
foo("1x","2y","3t1","3t2")
foo("1x","2y","3t1","3t2",d1="4d1",d2="4d2")

94. Try it!
▪#練習：寫⼀個輸⼊ N 個數字，回傳總和的函式。
94

95. Try it!
▪#練習：印出 1~100 有哪些質數
95

96. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
96

97. Software Engineering
97
Procedural
Programming
Modular
Programming
Objective Orient
Programming
Functional
Programming

98. Software Engineering
98
Modular
Programming
Objective Orient
Programming

99. Class and Object
99

100. 100
abstract
instance

101. 101
class object

102. 102
class object
State
Behavior

103. 103
class object
Properties
method

104. OOP Concept
▪Abstraction
▪Encapsulation => public, private
▪Inheritance
▪Polymorphism => 不同的類別，有相同的 method
▪Overloading => ⼀一個類別中相同的 method ，有不同的⾏行行為
▪Overriding => ⽗父⼦子相同的 method，改寫成不同的⾏行行為
104

105. Inheritance
▪base classes
▪derived class
105

106. Class Objects
106
1
2
3
4
5
6
7
8
class MyClass:
"""A simple example class"""
i = 12345
def f(self):
return 'hello world %s' % (self.i)

107. Class Objects
107
1
2
3
4
5
6
7
8
class MyClass:
"""A simple example class"""
def __init__(self, i):
self.i = i
def f(self):
return 'hello world %s' % (self.i)

108. Class and Object
108
1
2
3
4
5
6
7
8
class Animal:
def __init__(self, name):
self.name = name
def call():
return ‘汪汪’
a = Animal('動物')
print(a.name)
print(a.call())

109. 109
1
2
3
4
5
6
7
8
9
10
class BankAccount:
type = 'Normal Account'
def __init__(self, name):
self.userName = name
self.balance = 0.0
def __str__(self):
return self.name
11
12
13
14
15
16
17
18
19
20
21
22
def showBalance(self):
print self.balance
return
def withdrawMoney(self, amount):
self.balance -= amount
self.check()
return
def depositMoney(self, amount):
self.balance += amount
return
def check()
Creating a Class

110. 110
1
2
3
4
5
6
7
8
9
10
object1 = BankAccount("Im 1")
object1.userName
object1.depositMoney(100)
print object1.balance
object1.showBalance()
print object1.type
Create an Object
1
2
3
4
5
6
7
8
9
10
object2 = BankAccount("Im 2")
object2.userName
object2.depositMoney(200)
print object2.balance
object2.showBalance()
print object2.type

111. 111
1
2
3
4
5
6
7
8
9
10
account3 = BankAccount()
print(account3.__class__)
print(type(account3))
string = 'Cat'
print(string.__class__)
print(type(string))
Create an Object

112. Try it!
▪#練習：建⽴⼀個 Student 的類別，要包含姓名、性別、年齡，
也要可以修改資料。
▪class student()
▪ det __init__(self, name, sex, age):
▪ selt.name = name.
▪…
112

113. Try it!
▪#練習：利⽤上述建⽴的類別，宣告幾個物件，並放到⼀個 dict
保存。
▪TomObj = student(‘Tom’, ‘male’, 22)
▪stduents = {‘Tom’: TomObj , ‘Mary’: obj}
▪stduents.Tom.age
▪stduents.Mary.age
113

114. OOP Concept
▪Abstraction
▪Encapsulation => public, private
▪Inheritance
▪Polymorphism => 不同的類別，有相同的 method
▪Overloading => ⼀一個類別中相同的 method ，有不同的⾏行行為
▪Overriding => ⽗父⼦子相同的 method，改寫成不同的⾏行行為
114

115. Inherit
115
1
2
3
4
5
6
7
8
9
1
0
class Dog(Animal):
def __init__(self, name, age):
super().__init__(name)
self.age = age
# override
def call():
print('汪汪汪')
def call(ishungry):
print(’T____T')
d = Dog('⼩小⽩白', 13)
print(d.name)
1
2
3
4
5
6
7
8
class Animal:
def __init__(self, name):
self.name = name
def call():
return ‘汪汪’
a = Animal('動物')
print(a.name)
print(a.call())

116. Inherit
116
1
2
3
4
5
6
7
8
9
1
0
class Cat(Animal):
def __init__(self, name, age):
super().__init__(name)
self.age = age
# override
def call():
print(’喵喵喵')
d = Dog(‘⼩小花', 13)
print(d.name)
1
2
3
4
5
6
7
8
class Animal:
def __init__(self, name):
self.name = name
def call():
return ‘汪汪’
a = Animal('動物')
print(a.name)
print(a.call())

117. Inherit
117
1
2
3
4
5
6
7
8
9
10
class ExecutiveAccount( BankAccount ):
def requestCredit(self, amount):
self.balance += amount
executive = ExecutiveAccount()

118. OOP Concept
▪Abstraction
▪Encapsulation => public, private
▪Inheritance
▪Polymorphism => 不同的類別，有相同的 method
▪Overloading => ⼀一個類別中相同的 method ，有不同的⾏行行為
▪Overriding => ⽗父⼦子相同的 method，改寫成不同的⾏行行為
118

119. Private
119
1
2
3
4
5
6
7
8
9
10
class Human:
def __init__(self,h=0,w=0):
self.height=h
self.weight=w
def BMI(self):
return self.weight / ((self.height/100)**2)
a = Human(180,80)
print(a.height,a.weight)
print(a.BMI())

120. Private
120
1
2
3
4
5
6
7
8
9
10
class Human:
def __init__(self,h=0,w=0):
self.__height=h
self.__weight=w
def __BMI(self):
return self.__weight /
((self.__height/100)**2)
a = Human(180,80)
print(a.__height,a.__weight)
print(a.__BMI())

121. Private
121
1
2
3
4
5
6
7
8
9
10
class Human:
def __init__(self,h=0,w=0):
self.__height=h
self.__weight=w
def __BMI(self):
return self.__weight /
((self.__height/100)**2)
def getBMI(self):
return self.__BMI()
a = myclass.Human(180,80)
print(a.getBMI())

122. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
122

123. Error Exception
123
1
2
3
4
5
6
7
8
9
10
11
12
13
14
10 * (1/0)
4 + spam*3
'2' + 2

124. Error Exception
124
1
2
3
4
5
6
7
8
9
10
11
12
13
14
10 * (1/0)
# Traceback (most recent call last):
# File "<stdin>", line 1, in
<module>ZeroDivisionError: division by zero
4 + spam*3
# Traceback (most recent call last):
# File "<stdin>", line 1, in <module>NameError:
name 'spam' is not defined
'2' + 2
# Traceback (most recent call last):
# File "<stdin>", line 1, in <module>TypeError:
Can't convert 'int' object to str implicitly

125. try-except
125
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
try:
x = input("the first number:")
y = input("the second number:")
r = float(x)/float(y)
print(r)
except Exception as e:
print(e)
the first number: 2
the second number: 0
# float division by zero
the first number: 2
the second number: a
# could not convert string to float: a
the first number: 4
the second number: 2
# 2.0

126. Finally
126
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
try:
do something
except:
raise NameError('HiThere')
do something
finally
do something
try:
file = open("test.py")
except:
print('Read file error')
finally:
file.close()

127. Outline
▪Introduction
▪HelloWorld
▪Common Types & Operator
▪Flow Control
▪Function
▪Class
▪Exception
▪File IO
127

128. File Write
128
1
2
3
fh = open("example.txt", "w")
fh.write(”hello world")
fh.close()

129. File Read
129
1
2
3
fh = open("example.txt", ”r")
fh.read()
fh.close()

130. With
130
1
2
3
4
5
with open("example.txt", "w") as fh:
fh.write(”hello world")
with open("example.txt", "r") as fh:
fh.read()

131. mode
131
r 以只读⽅式打开⽂件。⽂件的指针将会放在⽂件的开头。这是默认模式。
r+ 打开⼀个⽂件⽤于读写。⽂件指针将会放在⽂件的开头。
w 打开⼀个⽂件只⽤于写⼊。如果该⽂件已存在则将其覆盖。如果该⽂件不存
在，创建新⽂件。
w+ 打开⼀个⽂件⽤于读写。如果该⽂件已存在则将其覆盖。如果该⽂件不存
在，创建新⽂件。
a 打开⼀个⽂件⽤于追加。如果该⽂件已存在，⽂件指针将会放在⽂件的结
尾。也就是说，新的内容将会被写⼊到已有内容之后。如果该⽂件不存在，
创建新⽂件进⾏写⼊。
a+ 打开⼀个⽂件⽤于读写。如果该⽂件已存在，⽂件指针将会放在⽂件的结
尾。⽂件打开时会是追加模式。如果该⽂件不存在，创建新⽂件⽤于读写。

132. Thanks for listening.
2017/08/07 (Tue.) Fundamental Python - Basic
Wei-Yuan Chang
v123582@gmail.com
v123582.github.io