实验4 函数与异常处理应用编程

1.实验任务1

print(sum)
sum = 42
print(sum)

def inc(n):
    sum = n + 1
    print(sum)
    return sum

sum = inc(7) + inc(7)
print(sum)

回答问题：不是。

line1：bulit-in

line3：global

line7：local

line11：enclosing

2.实验任务2

task2_1.py

# task2_1.py
def func1(a, b, c, d, e, f):
    return [a, b, c, d, e, f]

def func2(a, b, c, *, d, e, f):
    return [a, b, c, d, e, f]

def func3(a, b, c, /, d, e, f):
    return [a, b, c, d, e, f]

print(func1(1, 9, 2, 0, 5, 3))
print(func1(a=1, b=9, c=2, d=0, e=5, f=3))
print(func1(1, 9, 2, f=3, d=0, e=5))

print(func2(11, 99, 22, d=0, e=55, f=33))
print(func2(a=11, b=99, c=22, d=0, e=55, f=33))

print(func3(111, 999, 222, 0, 555, 333))
print(func3(111, 999, 222, d=0, e=555, f=333))

在line16后，尝试增加一行函数调用，重新运行程序

print( func2(11, 99, 22, 0, 55, 33) )

错误信息：

在line19后，尝试增加一行函数调用，重新运行程序

print(func3(a=111, b=999, c=222，0, 555, 333) )

错误信息：

task2_2.py

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

回答问题：

参数reverse的传递方式必须使用关键字传递。

task2_3.py

# 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))

3.实验任务3

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
print(solve.__doc__)
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()

4.实验任务4

def list_generator(a, b, c=1):
    list = []
    while a != b:
        list.append(a)
        a = a + c
    list.append(a)
    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)

5.实验任务5

def is_prime(n):
    a = 0
    for i in range(2, n):
        if n % i == 0:
            a = a + 1
        else:
            a = a + 0
    if n<=1 or a > 0:
        return False
    else:
        return True
for i in range(0,21):
    list=[]
    if i%2==0:
        for j in range(2,i):
            if is_prime(j):
                list.append(j)
            else:
                continue
        for m in list:
                if (i-m)in list:
                    print(f'{i}={m}+{i-m}')
                    break
                else:
                    continue
    else:
        continue

6.实验任务6

def encoder(n):
    import string
    a = string.ascii_letters[5:26] + string.ascii_letters[:5]+string.ascii_letters[31:52]+string.ascii_letters[26:31]
    trantab=n.maketrans(string.ascii_letters,a)
    return n.translate(trantab)
def decoder(n):
    import string
    a = string.ascii_letters[5:26] + string.ascii_letters[:5] + string.ascii_letters[31:52]+string.ascii_letters[26:31]
    trantab = n.maketrans(a,string.ascii_letters)
    return n.translate(trantab)
n=input('输入英文文本:')
print(f'编码后的文本:{encoder(n)}')
print(f'对编码后的文本解码:{decoder(encoder(n))}')

7.实验任务7

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

实验总结：

python真的好难，好累哟。：)