实验4 函数与异常处理应用编程

 

#task1.py
print(sum)
sum = 42
print(sum)
def inc(n):
    sum = n+1
    print(sum)
    return sum
sum = inc(7) + inc(7)
print(sum)

1.Built-in

2.Global

3.Local

4.Global 

#task2_2.py
list1 = [1, 9, 8, 4]
print( sorted(list1) )
print( sorted(list1, reverse=True) )
print( sorted(list1, True) )

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

#task3.py
def solve(a, b, c):
    '''
    求解一元二次方程, 返回方程的两个根
    :para: a,b,c: int 方程系数
    :return: tuple
    '''
    delta = b*b - 4*a*c
    delta_sqrt = abs(delta)**0.5
    p1 = -b/2/a;
    p2 = delta_sqrt/2/a
    if delta>=0:
        root1 = p1 + p2
        root2 = p1 - p2
    else:
        root1 = complex(p1, p2)
        root2 = complex(p1, -p2)
    return root1, root2


while True:
    try:
       a,b,c = eval(input('Enter eqution coefficient: '))
       if a == 0:
           raise
    except:
        print('invalid input, or, a is zero')
        break
    else:
        root1, root2 = solve(a, b, c)
        print(f'root1 = {root1:.2f}, root2 = {root2:.2f}')
        print()

加一行代码会把说明信息打印出来

#task4.py
def list_generator(a,b,step=1):
    list=[]
    while a<=b:
        list.append(a)
        a+=step
    return list
list1 = list_generator(-5, 5)
print(list1)
list2 = list_generator(-5, 5, 2)
print(list2)
list3 = list_generator(1, 5, 0.5)
print(list3)

#task5.py
def is_prime(n):
    for i in range(2,int(n**0.5)+1):
        if n%i==0:
            return False
    else:
        return True
for j in range(2,21,2):
    for k in range(2,j):
        if is_prime(j-k):
            print(f'{j}={k}+{j-k}')
            break

 

#task6.py
def encoder(text:str):
    ans=[]
    for n in text:
        x=ord(n)
        if 65<=x<=90:
            ans.append(chr((x-60)%26+65))
        elif 97<=x<=122:
            ans.append(chr((x-92)%26+97))
        else:
            ans.append(n)
    return ''.join(ans)

def decoder(text1):
    ans1=[]
    for n in text1:
        x1=ord(n)
        if 65 <= x1 <= 90:
            ans1.append(chr((x1 - 44) % 26 + 65))
        elif 97 <= x1 <= 122:
            ans1.append(chr((x1 - 76) % 26 + 97))
        else:
            ans1.append(n)
    return ''.join(ans1)



text=input('输入英文文本:')
text1=encoder(text)
print(f'编码后的文本:{text1}')
print(f'解码后的文本:{decoder(text1)}')

 

#task7.py
def collatz(n):
    if n%2==0:
        return n/2
    else:
        return 3*n+1
try:
    n=eval(input('Enter a positive integer:'))
    if type(n)!=int or n<=0:
        raise ValueError and NameError
except ValueError and NameError:
    print('Error: must be a positive integer')
else:
    list=[n]
    while n!=1:
        n=collatz(n)
        list.append(n)
    print(list)