实验4 函数与异常处理编程

实验任务1

task1.py

 1 print(sum)
 2 sum = 42
 3 print(sum)
 4  
 5 def inc(n):
 6     sum = n+1
 7     print(sum)
 8     return sum
 9  
10 sum = inc(7) + inc(7)
11 print(sum)

回答：不是，line1是Built-in内置作用域，line3和line11是Global全局作用域，line7是Local局部作用域。

实验任务2

task2_1.py

 1 def func1(a, b, c, d, e, f):
 2     return [a,b,c,d,e,f]
 3 def func2(a, b, c,*, d, e, f):
 4     return [a,b,c,d,e,f]
 5 def func3(a, b, c, /, d, e, f):
 6     return [a,b,c,d,e,f]
 7 # func1调用：按位置传递、按参数传递都可以
 8 print(func1(1,9,2,0,5,3))
 9 print(func1(a=1, b=9, c=2, d=0, e=5, f=3))
10 print(func1(1,9,2, f=3, d=0, e=5))
11 # func2调用：d,e,f必须按关键字传递
12 print(func2(11, 99, 22, d=0, e=55, f=33))
13 print(func2(a=11, b=99, c=22, d=0, e=55, f=33))
14 # func3调用：a,b,c必须按位置传递
15 print(func3(111, 999, 222, 0, 555, 333))
16 print(func3(111, 999, 222, d=0, e=555, f=333))

task2_2.py

1 list1 = [1, 9, 8, 4]
2 print(sorted(list1))
3 print(sorted(list1, reverse=True))
4 print(sorted(list1, True))

task2_3.py

1 def func(a, b, c, /, *, d, e, f):
2     return([a,b,c,d,e,f])
3 print(func(1,2,3,d=4,e=5,f=6))

实验任务3

task3.py

 1 def solve(a, b, c):
 2     '''
 3     求解一元二次方程, 返回方程的两个根
 4 
 5     :para: a,b,c: float 方程系数
 6     :return: tuple
 7     '''
 8     delta = b*b - 4*a*c
 9     delta_sqrt = abs(delta)**0.5
10     p1 = -b/2/a
11     p2 = delta_sqrt/2/a
12 
13     if delta >= 0:
14         root1 = p1 + p2
15         root2 = p1 - p2
16     else:
17         root1 = complex(p1, p2)
18         root2 = complex(p1, -p2)
19 
20     return root1, root2
21 
22 
23 while True:
24     try:
25         t = input('输入一元二次方程系数a b c, 或者，输入#结束: ')
26         if t == '#':
27             print('结束计算，退出')
28             break
29         a, b, c = map(float, t.split())
30         if a == 0:
31             raise ValueError('a = 0, 不是一元二次方程')
32     except ValueError as e:
33         print(repr(e))
34         print()
35     except:
36         print('有其它错误发生\n')
37     else:
38         root1, root2 = solve(a, b, c)
39         print(f'root1 = {root1:.2f}, root2 = {root2:.2f}')
40         print()

实验任务4

task4.py

 1 def list_generator(x,y,s=1):
 2     l = []
 3     while x<=y:
 4         l.append(x)
 5         x = x+s
 6     return l
 7 
 8 list1 = list_generator(-5, 5)
 9 print(list1)
10 
11 list2 = list_generator(-5, 5, 2)
12 print(list2)
13 
14 list3 = list_generator(1, 5, 0.5)
15 print(list3)

实验任务5

task5.py

 1 def is_prime(n):
 2     if n==2:
 3         return True
 4     else:
 5         for i in range(2,int(n**0.5)+1):
 6             if n%i==0:
 7                 return False
 8         return True
 9 
10 for i in  range(4,21,2):
11     for s in range(2,i):
12         if is_prime(i-s):
13             print(f'{i} = {s} +{i-s}')
14             break

实验任务6

task6.py

 1 # 编码函数encoder()定义
 2 def encoder(a):
 3     c = ''
 4     for i in a:
 5         if i.isalpha():
 6             temp = ord(i)+5
 7             if chr(temp).isalpha():
 8                 c += chr(temp)
 9             else:
10                 c += chr(temp-26)
11         else:
12             c += i
13     return c
14 
15 # 解码函数decoder()定义
16 def decoder(x):
17     z = ''
18     for i in x:
19         if i.isalpha():
20             temp = ord(i)-5
21             if chr(temp).isalpha():
22                 z+=chr(temp)
23             else:
24                 z+=chr(temp+26)
25         else:
26             z += i
27     return z
28 
29 # 主体代码逻辑
30 text = input('输入英文文本: ')
31 
32 encoded_text = encoder(text)
33 print('编码后的文本: ', encoded_text)
34 
35 decoded_text = decoder(encoded_text)
36 print('对编码后的文本解码: ', decoded_text)

实验任务7

task7.py

 1 def collatz(n):
 2     l = [n]
 3     while l[-1] !=1:
 4         if l[-1]%2==0:
 5             l.append(l[-1]//2)
 6         else:
 7             l.append(l[-1]*3+1)
 8     return l
 9 
10 try:
11     x = int(input('Enter a positive integer:'))
12     if x <= 0:
13         raise
14 except:
15     print('Error:must be a positive integer')
16 else:
17     print(collatz(x))

实验任务8

task8.py

 1 # 函数func()定义
 2 def func(n):
 3     result = 1
 4     for i in range(n):
 5         result *= 2
 6     return result-1
 7 
 8 while True:
 9     x = input()
10     if x == '#':
11         print('计算结束')
12         break
13     n = int(x)
14     ans = func(n)
15     print(f'n = {n}, ans = {ans}')