Python Fundamentals - Basic | WeiYuan

Python Fundamentals - Basic

Transcript

1. Python Fundamentals - Basic 給新⼿的 Python 程式設計 | WeiYuan
2. § 全端工程師 + 資料科學家 ST2DE 計劃發起人，擅長網站開發與資料科學的雙棲 工程師，熟悉的語言是 Python 跟 JavaScript，喜歡 用程式與技術的思維解決問題。 - 2018 總統盃黑客松 冠軍隊伍 - 2017 資料科學愛好者年會(DSCONF) 講師 - 2017 行動科技年會(MOPCON) 講師 - 2016 微軟 Imagine Cup 台灣區冠軍 site: v123582.tw / line: weiwei63 mail: v123582@gmail.com
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 link § High-level and Interpreted programming language § OOP + FP multi-paradigm § 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: packages manager of python <- default § Pyenv, Vitrualenv <- need to install 5
6. 6 Explicit 清楚 Beautiful 漂亮 Simple 簡單
7. 7 Explicit 清楚 Beautiful 漂亮 Simple 簡單
9. Python 2.x or Python 3.x ? 9
10. Python 2.x or Python 3.x ? 10
11. Python 2.x or Python 3.x ? 11 1. Python 團隊將於 2020 年 1 月 1 日停止支持 Python 2.7 2. Python 正式正名代表為 Python3
13. 13 選擇 Python 做為程式語言的兩個原因： ① 程式語法簡單好寫 ② 第三方資源豐富
14. Python Ecosystem for Data Science § Request、beatifulsoup、Scrapy § NumPy、 SciPy、 Pandas § Matplotlib、 Seaborn、 Bokeh、 Plotly § Statsmodels、SciKit-Learn、xgboost § TensorFlow(Theano)、Pytorch、Keras § NLTK、Gensim 14
15. Python Ecosystem for Data Science § Request、beatifulsoup、Scrapy =>資料收集 § NumPy、 SciPy、 Pandas => 資料前處理 § Matplotlib、 Seaborn、 Bokeh、 Plotly => 資料視覺化 § Statsmodels、SciKit-Learn、xgboost => 資料模型訓練 § TensorFlow(Theano)、Pytorch、Keras => 深度學習 § NLTK、Gensim => 自然語言與文本資料處理 15
16. Runtime & Develop § 怎麼執行 Python 程式？ shell / command / Jupyter notebook § 在哪裡寫 Python 程式碼？ editor / IDE 16
17. Python 環境、套件安裝與使用 一個開發環境包含「程式語言執行環境」、「開發/編輯環境」、 「第三方套件」。可能會存在版本或是專案上的差異，因此常見的 管理工具有以下： § Anaconda 集成式開發軟體 § PIP 套件管理工具 § Pyenv 多版本Python管理工具 § Virtualenv 虛擬環境 17
18. Python 環境、套件安裝與使用 18 § Anaconda是一個免費開源的Python和R語言的發行版本，用於計 算科學，Anaconda致力於簡化包管理和部署。Anaconda的包使 用軟體包管理系統Conda進行管理。
19. pip 19
20. 20 #Note. 套件管理⼯具：替開發者下載、保存第三⽅套件，在程式 中可以載⼊使⽤
21. 21 #Note. 套件管理⼯具：替開發者下載、保存第三⽅套件，在程式 中可以載⼊使⽤ 1. 為什麼要用 pip？ 2. pip 是從哪裡下載套件的？ 3. 套件會被 pip 存放在哪？
22. 執行位置 – 方法一 22 1.從開始找到 Anaconda 2. 點選 Prompt，打開黑色視窗 3.開始輸入 pip 指令
23. 執行位置 – 方法二 23
24. 相關的開發管理工具 § PIP 套件管理工具 § Pyenv 多版本Python管理工具 § Virtualenv 虛擬環境 24
25. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 25
26. Hello World Variable and Assign 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) Import Library Encoding Declaration Comment Indentation and Block Input and Output
27. Hello World 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) Encoding Declaration Comment
28. Hello World 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) Import Library § Library = module = package = a set of functions
29. Hello World Variable and Assign 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) § Case Sensitivity § Weekly/Loosely Typed
30. Hello World 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) Indentation and Block Spaces of Tab ?
31. Hello World 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 #!/usr/bin/env python3 # -*- coding: utf-8 -*- # ['False', 'None' . . .] import this, keyword from keyword import kwlist from keyword import * keywords = kwlist if len(keywords) > 0: print(keywords) x = input("Input Something...") print("%s" % (x)) Input and Output
32. Outline § Introduction § HelloWorld § Data Types & Operator § Flow Control § Function § Class § Exception § File IO 32
33. Common Types & Operator 33 Primitive Container
34. Primitive Types § Numeric type （int / float） § String type （str） § Boolean type （bool） 34
35. Built-in Functions 35 1 2 3 4 5 6 type() dir() help() https://docs.python.org/3/library/functions.html
36. Common Types & Operator 36 expression = operator (symbols)+ operand (variables)
37. Common Types & Operator 37 expression = operator (symbols)+ operand (variables) arithmetic comparison logical bitwise
38. Numeric type （int / float） 38 1 2 3 4 5 6 7 8 9 10 a = 20 a, b, c, d = 20, 5.5, True print(type(a)) # <class 'int'> print(type(b)) # <class 'float'> print(type(c)) # <class 'bool'> print(isinstance(a, int)) # True print(isinstance(b, int)) # False
39. Numeric type （int / float） 39 1 2 3 4 5 6 7 8 9 10 11 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
40. Numeric type （int / float） 40 1 2 3 4 5 6 7 8 9 10 11 # 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...
41. 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 41
42. Try it! 42 1 2 3 4 5 6 7 8 9 10 11 1 + 3*2 # 1 + 3**2 # (1 + 3)*2 # 1 + 3 / 2 *2 # 1 + 3 // 2 *2 # 1 + 3 / 2 **2 # 1 + 3 // 2 **2 # int(1 + 3 / 2 *2) # float(1 + 3 // 2 **2) # § #練習：Set the following variables to the corresponding
43. Try it! 43 1 2 3 4 5 6 7 8 9 10 11 a = input() b = input() ''' Your Code ''' print(‘The sum of ’, a, ‘and’ ,b , ‘is’, a+b) § #練習：Add two numbers
44. Try it! 44 1 2 3 4 5 6 7 8 9 10 11 a = input() b = input() ''' Your Code ''' print(‘The sum of ’, a, ‘and’ ,b , ‘is’, a+b) § #練習：承上題，要如何改成 a, b, c, d 四個輸⼊：
45. Try it! 45 1 2 3 4 5 6 7 8 9 10 11 num = 9 ''' Your Code ''' print('The square root of %0.3f is %0.3f' % (num ,num_sqrt)) § #練習：Find the Square Root
46. Try it! 46 1 2 3 4 5 6 7 8 9 10 11 a = 5 b = 10 ''' Your Code ''' print(a, b) # 10, 5 § #練習：Swap Two Variables
47. String Type - Operations 47 1 2 3 4 5 6 7 8 9 10 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))
48. String Type - Index & Slice 48 1 2 3 4 5 6 7 8 9 10 s = 'hello world' s[0], s[1], s[-1] s[0:5], s[0:len(t)], s[:] s[1:5:2], s[::-1]
49. String Type - Methods 49 1 2 3 4 5 6 7 8 9 10 b = 'hello world' dir(b)
50. String Type 50 1 2 3 4 5 6 7 8 9 10 split() find() replace() len() lower() upper() isdigit() isnumeric() isalpha()
51. § Question：What is different among True, ‘True’, true ? 51
52. Try it! § #練習：Write a Python program to get a string made of the first 2 and the last 2 chars from a given a string. If the string length is less than 2, return instead of the empty string. • Sample Input: w3resource • Sample Output: w3ce 52
53. Try it! § #練習：將字串當中的 not that poor 換成 good 。 • Sample Input: The company is not that poor! • Sample Output: The company is good! 53
54. Try it! § #練習：將字串當中的 not … poor 換成 good 。 • Sample Input: The company is not that poor! • Sample Output: The company is good! 54
55. 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。 55
56. #Note. Formatting String 56 1 2 3 4 5 6 7 8 9 10 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}'
57. #Note. Formatting String 57 1 2 3 4 5 6 7 8 9 10 a, b, sum = 2, 3, 5 '%s + %s = %s ' % (a, b, sum) '%d + %d = %d ' % (a, b, sum) '%f + %f = %f ' % (a, b, sum)
58. #Note. Formatting String 58 1 2 3 4 5 6 7 8 9 10 a, b, c = ‘x’, ‘y’, ‘z’ '%s, %s, %s ' % (a, b, c) '%d, %d, %d ' % (a, b, c) '%f, %f, %f ' % (a, b, c)
59. #Note. Formatting String 59 1 2 3 4 5 6 7 8 9 10 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)
60. #Note. Formatting String 60 1 2 3 4 5 6 7 8 9 10 %s => string %d => decimal %f => float \n => new line \t => tab
61. § Question：Why do I use Formatting String? 61
62. Container Types 62 § list [,] => mutable sequence § tuple (,) => immutable sequence § dict {:,} => mutable collection of key-value mapped element § set {,} => mutable collections of unique elements
63. Container Types 63 § list [,] => mutable sequence § tuple (,) => immutable sequence § dict {:,} => mutable collection of key-value mapped element § set {,} => mutable collections of unique elements
64. Container Types 64 § list [,] => mutable sequence § tuple (,) => immutable sequence § dict {:,} => mutable collection of key-value mapped element § set {,} => mutable collections of unique elements
65. Container Types 65 § list [,] => # l = [1, 2, 3, 4], l[0] = 999 § tuple (,) => # t = (1, 2), t[0] = 999 § dict {:,} => # d = {1: 100, 2: 200}, d[1] § set {,} => # s = {1, 2, 3}
66. List 66 § List – Operations § List – Index & Slice § List - Methods
67. List - Operations 67 1 2 3 4 5 6 7 8 9 10 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
68. List – Index & Slice 68 1 2 3 4 5 6 7 8 9 10 L = [1, 2, 3, 4, 5, 6] L[0], L[1], L[-1] L[0] = 999 L[0:5], L[0:len(L)], L[:] L[1:5:2], L[::-1]
69. § Question：How does arithmetical operation with string? 69
70. List - Methods 70 1 2 3 4 5 6 7 8 9 10 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]
71. List - Operations 71 1 2 3 4 5 6 7 8 9 10 my_list.count(2) # 1 len(my_list) # 2 sum(my_list) # 5 ‘2, 3’.split(‘, ’) # [2, 3] ', '.join([2, 3]) # '2, 3'
72. Try it! § #練習：有一個列表，其中包括 10 個元素，例如這個列表是 [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] 72
73. Try it! § #練習：有一個列表，其中包括 10 個元素，例如這個列表是 [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] 73
74. #Discussion 1. append, extend, + 三種方法有什麼不一樣？ 2. reversed(L), L.reverse(), [::-1] 3. sorted(L), L.sort() 74
75. 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] 75
76. Tuple 76 § Tuple – Operations § Tuple – Index & Slice § Tuple – Destructuring & Swaping
77. Tuple - Operations 77 1 2 3 4 5 6 7 8 9 10 t1 = (1, 2, 3) t1 = (4, 5, 6) t1 + t2 t1 * 2
78. Tuple – Index & Slice 78 1 2 3 4 5 6 7 8 9 10 t = (1, 2, 3, 4, 5, 6) t[0], t[1], t[-1] t[0] = 999 t[0:5], t[0:len(t)], t[:] t[1:5:2], t[::-1]
79. § Question：How does arithmetical operation with string & list? 79
80. Destructuring & Swaping 80 1 2 3 4 5 6 7 8 9 10 (a, b) = my_list (a, b) = (b, a)
81. Try it! § #練習：Swap Two Variables 81 1 2 3 4 5 6 7 8 9 10 11 a = 5 b = 10 ''' Your Code ''' print(a, b) # 10, 5
82. Dictionary 82 § Dictionary – Operations § Dictionary – Unordered to Ordered § Dictionary – Key Error
83. Dictionary – Operations 83 1 2 3 4 5 6 7 8 9 10 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']
84. Dictionary – Unordered to Ordered 84 1 2 3 4 5 6 7 8 9 10 my_dict.items() # dict_items([('Mark', 1), ('Mary', 2) ]) my_dict.keys() # dict_keys(['Mark', 'Mary']) my_dict.values() # dict_values([1, 2])
85. Dictionary – Key Error 85 1 2 3 4 5 6 7 8 9 10 my_dict['Tom'] # Traceback (most recent call last): # File "<stdin>", line 1, in <module> # KeyError: ‘Tom’ my_dict.get('Tom', ''), my_dict # '', {'Mark': 1, 'test': 0} my_dict.setdefault('Tom', 3), my_dict # 3, {'Tom': 3, 'Mark': 1, 'test': 0}
86. Try it! § #練習： Write a Python program to concatenate following dictionaries to create a new one 86 1 2 3 4 5 6 7 8 9 10 11 # Input: dic1={1:10, 2:20} dic2={3:30, 4:40} dic3={5:50, 6:60} ''' Your Code ''’ # Output: {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60}
87. Try it! § #練習：Write a Python program to check if a given key already exists in a dictionary. § 87 1 2 3 4 5 6 7 8 9 10 11 # Input: d = {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60} key = input() ''' Your Code ''' # Output: Yes, the key is in this dict. or # No, the key is not in this dict.
88. Set 88 § Set – Operations
89. Set – Operations 89 1 2 3 4 5 6 7 8 9 10 dmins = {'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}
90. Try it! § #練習： Illustrate Different Set Operations 90 1 2 3 4 5 6 7 8 9 10 11 # 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
91. Try it! § #練習： Remove the repeated elements from the list, and sort it Decreasingly. 91 1 2 3 4 5 6 7 8 9 10 11 l = [1, 1, 3, 9, 7, 8, 8, 8] ''' Your Code ''' # Output: [9, 8, 7, 3, 1]
92. Container Types 92 § list [,] => Operations / Index & Slice / Methods § tuple (,) => Operations / Index & Slice /Destructuring & Swaping § dict {:,} => Operations / Unordered to Ordered / Key Error § set {,} => Operations
93. 93 § 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 ?
94. 94 Reference: https://www.linkedin.com/pulse/mutable-vs-immutable-objects-python-megha-mohan
95. 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) 95
96. iterator, iterable, iteration 96 Reference: http://nvie.com/posts/iterators-vs-generators/
97. iterator, iterable, iteration 97 1 2 3 4 5 6 7 8 9 10 11 12 13 14 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))
98. iterator, iterable, iteration 98 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 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))
99. bulit-in method 99 1 2 3 4 5 6 7 8 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
100. Try it! § #練習：要求使⽤者輸⼊ n ，印出從 n 平⽅的對數值（Log） • hint：引入一個 math 的函式庫，並且利用 dir 與 math 查看 log 函式怎 麼使用 100
101. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 101
102. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 102
103. Common Types & Operator § Numeric type • int, float, bool, complex • expression => operator + operand § String type § Container type • list, tuple, dict, set 103 § expression = operator + operand (varibles) • arithmetic, comparison arithmetic comparison logical bitwise
104. Flow Control § Logical Operator § Comparison Operator 104 1 2 3 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
105. Flow Control § Logical Operator => return Boolean § Comparison Operator => return Boolean 105 1 2 3 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
106. What it truth? 106
107. What it truth? 107
108. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 108 1 2 3 4 5 6 7 8 9 if condition: ... elif condition: ... else: ... a = ... if condition else ...
109. 109 Reference: http://swcarpentry.github.io/training-course/2013/03/concept-map-conditional-statements-python/ § operator • boolean/logical • comparison
110. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 110 1 2 while condition: ....
111. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 111 1 2 3 4 5 for i in [...]: ... a = [i for i in [...]] # list b = (i for i in [...]) # generator
112. Try it! § #練習：有一個列表，其中包括 10 個元素，例如這個列表是 [1, 2, 3, 4, 5, 6, 7, 8, 9, 0],要求將列表中的每個元素一次向前移動一 個位置，第一個元素到列表的最後，然後輸出這個列表。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] 112
113. Try it! § #練習：在數學中，用 n! 來表示階乘，例如，4! =1×2×3×4 =24。 請寫一個程式，讓使用者輸入 n，印出 n! 1. 用 for 迴圈完成 2. 用 while 迴圈完成 113
114. 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。 114
115. Try it! § #練習："Please count the character here." 115 1 2 3 4 5 6 7 8 9 10 # {'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}
116. Try it! § #練習："Here are UPPERCASE and lowercase chars." 116 1 2 3 4 5 6 7 8 9 10 # {'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']}
117. Try it! § #練習：畫各種三⾓形與變形 117 * ** *** **** * ** *** **** * *** ***** ******* * *** ***** ******* ********* ******* ***** *** *
118. § https://leetcode.com/problems/two-sum/description/ 118
119. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 119
120. Flow Control § if - elif - else § while § for in § break, continue § range(), zip(), enumerate() 120 1 2 3 4 5 6 7 8 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)
121. More zip() … 121 1 2 3 4 5 6 7 8 9 10 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
122. More zip() … 122 1 2 3 4 5 6 7 8 9 10 11 12 13 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]
123. Try it! § #練習：建⽴⼀個 1 - 10 平⽅的數列。 123
124. 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。 124
125. 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"} 125
126. 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 126
127. 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。 127
128. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 128
129. Function 129 1 2 3 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
130. Basic Method for Call Function 130 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})
131. Try it! § #練習：寫⼀個計算平⽅的函式。 131
132. Try it! § #練習：寫⼀個計算平⽅根的函式。 132
133. Try it! § #練習：寫⼀個回傳⼀次⽅，⼆次⽅，…，到指定次⽅的函式。 133
134. *args 134 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'})
135. **kargs 135 1 2 3 4 5 def foo(**kargs): print(kargs) foo(a=1,b=2,c=3) # {'a': 1, 'c': 3, 'b': 2}
136. type1 + type2 + type3 136 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'}
137. 137 Reference: http://swcarpentry.github.io/training-course/2013/05/concept-map-python-functions/
138. Try it! § #練習：以下程式會如何輸出？ 138 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")
139. Try it! § #練習：寫⼀個輸⼊ N 個數字，回傳總和的函式。 139
140. Try it! § #練習：印出 1~100 有哪些質數 140
141. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 141
142. Software Engineering 142 Procedural Programming Modular Programming Objective Orient Programming Functional Programming
143. Software Engineering 143 Modular Programming Objective Orient Programming
144. Class and Object 144
145. 145 abstract instance
146. 146 class object
147. 147 class object State Behavior
148. 148 class object Properties method
149. OOP Concept § Abstraction § Encapsulation => public, private § Inheritance § Polymorphism => 不同的類別，有相同的 method § Overloading => 一個類別中相同的 method ，有不同的行為 § Overriding => 父子相同的 method，改寫成不同的行為 149
150. Inheritance § base classes § derived class 150
151. Class Objects 151 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)
152. Class Objects 152 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)
153. Class and Object 153 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())
154. 154 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
155. 155 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
156. 156 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
157. 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. § … 157
158. 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 158
159. OOP Concept § Abstraction § Encapsulation => public, private § Inheritance § Polymorphism => 不同的類別，有相同的 method § Overloading => 一個類別中相同的 method ，有不同的行為 § Overriding => 父子相同的 method，改寫成不同的行為 159
160. Inherit 160 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())
161. Inherit 161 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())
162. Inherit 162 1 2 3 4 5 6 7 8 9 10 class ExecutiveAccount( BankAccount ): def requestCredit(self, amount): self.balance += amount executive = ExecutiveAccount()
163. OOP Concept § Abstraction § Encapsulation => public, private § Inheritance § Polymorphism => 不同的類別，有相同的 method § Overloading => 一個類別中相同的 method ，有不同的行為 § Overriding => 父子相同的 method，改寫成不同的行為 163
164. Private 164 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())
165. Private 165 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())
166. Private 166 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())
167. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 167
168. Error Exception 168 1 2 3 4 5 6 7 8 9 10 11 12 13 14 10 * (1/0) 4 + spam*3 '2' + 2
169. Error Exception 169 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
170. try-except 170 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
171. Finally 171 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()
172. Outline § Introduction § HelloWorld § Common Types & Operator § Flow Control § Function § Class § Exception § File IO 172
173. File Write 173 1 2 3 fh = open("example.txt", "w") fh.write(”hello world") fh.close()
174. File Read 174 1 2 3 fh = open("example.txt", ”r") fh.read() fh.close()
175. With 175 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()
176. mode 176 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。
177. Thanks for listening. 2017/08/07 (Tue.) Fundamental Python - Basic Wei-Yuan Chang v123582@gmail.com v123582.github.io