实验4 函数与异常处理编程-JZTXT

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)

sum: line1:内置函数sum函数名称

line3:赋值一个新变量的名称

line7:局部变量

line11:全局变量

实验任务2

task2_2.py

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

在Python内置函数sorted（）中，参数reverse的传递方式必须使用关键字传递。

task2_3.py

1 def func(a, b, c, /, *, d, e, f):
2     return( [a,b,c,d,e,f] )
3 
4 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 print(solve.__doc__)
24 while True:
25     try:
26         t = input('输入一元二次方程系数a b c, 或者，输入#结束: ')
27         if t == '#':
28             print('结束计算，退出')
29             break
30         a, b, c = map(float, t.split())
31         if a == 0:
32             raise ValueError('a = 0, 不是一元二次方程')
33     except ValueError as e:
34         print(repr(e))
35         print()
36     except:
37         print('有其它错误发生\n')
38     else:
39         root1, root2 = solve(a, b, c)
40         print(f'root1 = {root1:.2f}, root2 = {root2:.2f}')
41         print()

实验任务4

task4.py

 1 def list_generator(a,b,c=1):
 2     list=[]
 3     while a<=b:
 4         list.append(a)
 5         a+=c
 6     return list
 7 
 8 
 9 list1 = list_generator(-5, 5)
10 print(list1)
11 
12 list2 = list_generator(-5, 5, 2)
13 print(list2)
14 
15 list3 = list_generator(1, 5, 0.5)
16 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,n):
 6             if n%i==0:
 7                 return False
 8                 break
 9         else:
10             return True
11 
12 for i in range(4,21,2):
13     for x in range(2,i):
14         if is_prime(x):
15             if (i-x)>1 and is_prime(i-x):
16                 print(f'{i} = {x} + {i-x}')
17                 break

实验任务6

task6.py

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

实验任务7

task7.py

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

实验任务8

task8.py

 1 def func(n):
 2     if n==0:
 3         return 0
 4     else:
 5         return func(n-1)*2+1
 6 
 7 while True:
 8     x = input()
 9     if x == '#':
10         print('计算结束')
11         break
12     n = int(x)
13     ans = func(n)
14     print(f'n = {n}, ans = {ans}')