变量命名赋值规则
1 # variables - placeholders for important values
2 # used to avoid recomputing values and to
3 # give values names that help reader understand code
4
5
6 # valid variable names - consists of letters, numbers, underscore (_)
7 # starts with letter or underscore
8 # case sensitive (capitalization matters)
9
10 # legal names - ninja, Ninja, n_i_n_j_a
11 # illegal names - 1337, 1337ninja
12
13 # Python convention - multiple words joined by _
14 # legal names - elite_ninja, leet_ninja, ninja_1337
15 # illegal name 1337_ninja
16
17
18
19 # assign to variable name using single equal sign =
20 # (remember that double equals == is used to test equality)
21
22 # examples
23
24 my_name = "Joe Warren"
25 print my_name
26
27 my_age = 51
28 print my_age
29
30 # birthday - add one
31
32 #my_age += 1
33 print my_age
34
35
36 # the story of the magic pill
37
38 magic_pill = 30
39 print my_age - magic_pill
40
41 my_grand_dad = 74
42
43 print my_grand_dad - 2 * magic_pill
44
45
46
47
48
49
50
51
52
53 # Temperature examples
54
55 # convert from Fahrenheit to Celsuis
56 # c = 5 / 9 * (f - 32)
57 # use explanatory names
58
59 temp_Fahrenheit = 212
60
61 temp_Celsius = 5.0 / 9.0 * (temp_Fahrenheit - 32)
62
63 print temp_Celsius
64
65 # test it! 32 Fahrenheit is 0 Celsius, 212 Fahrenheit is 100 Celsius
66
67
68 # convert from Celsius to Fahrenheit
69 # f = 9 / 5 * c + 32
70
71 temp_Celsius = 100
72
73 temp_Fahrenheit = 9.0 / 5.0 * temp_Celsius + 32
74
75 print temp_Fahrenheit
76
77
78 # test it!
