1 #!/user/bin/env python
2 # -*- coding:utf-8 -*-
3
4 # Single-Line Comments
5
6 """
7 multiline Comments
8 """
9
10 """
11 1. Variable
12 Weak Type : No clear type, the specific type depends on the value
13 number = 10
14 print(type(number)
15 number = "10"
16 print(type(number))
17 2. Statement of Variables
18 format : Variable = value
19 Naming rules for Variable:
20 It can only be composed of letters, numbers and underscores
21 Can not start with numbers
22 Can not use keywords
23 import keyword
24 print(keyword.kwlist)
25 Case-sensitive
26 understand By name
27 3. Types of Variables
28 str : name = "YeYuanXinZhiZhu"
29 msg = '''
30 Use three quotation marks in reserved format
31 '''
32 Predefined escape characters
33 \\, \', \", \r, \t, \n
34 combine with "r", keep the original format
35 string = r"hello \table"
36 int : salary = 499999
37 float : salary = 499999.99
38 bool : flag = True, flag = False
39 byte : b = b"hello"
40 Unique types of Python (Container) :
41 list : scores = [90, 81, 51, 100, 69]
42 tuple : scores = (90, 81, 51, 100, 69)
43 set : scores = {90, 81, 51, 100, 69, 90, 81}
44 duplicate elements are not allowed
45 dict : scores = {"GeBiCunGaHa": 90, "YeYuanXinZhiZhu": 81}
46 4. Use of Variables and Operators
47 Arithmetic Operators : + - * / % ** //
48 Assigment Operators : = += -= /= %=
49 Relational Operators : == != > < >= <= is
50 Logical Operators : and or not
51 Tt is the case of False : "" 0 None
52 Bitwise Operators :
53 binary : a = 0b01000101
54 octal : b = oct(a)
55 decimal : c = int(a)
56 hexadecimal : d = hex(a)
57
58 computer operations :
59 converting -3 to binary :
60 converting 3 to binary :
61 original code : 0000 0011
62 Invert code of 3 :
63 inverse coed : 1111 1100
64 Invert code of 3 + 1 :
65 complement code : 1111 1101
66
67 bit operation : & | ~
68 ^(same is false, different is true)
69 >> <<
70 Member Operators : in, not in
71 Identity Operators : is, is not
72 Ternary Operators : [] if [] else []
73
74 5. Sentence
75 Conditional Statement
76 if conditional:
77 pass
78 else:
79 pass
80
81 Multiple Conditional Judgment:
82 if conditional:
83 pass
84 elif conditional:
85 pass
86 elif conditional:
87 pass
88 else:
89 pass
90
91 scene :
92 Parking Management System
93 Bank Management System
94 Loop Statement
95 Avoiding death circle:
96 Modify circle conditions;
97 Set the end condition in the loop body
98
99 while conditions:
100 loop body
101
102 while conditions:
103 loop body
104 else:
105 pass
106
107 for i in [iterable object]
108 loop body
109
110 for i in [iterable object]
111 loop body
112 else:
113 pass
114 Goto Statement
115 break : jump out of the loop structure
116 continue : skip the circle and continue with the next one
117 """
