实验4 函数与异常处理编程

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)

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答: 不是,

第一行中的"sum"是一个未定义的变量,第二行中"sum"的作用域是整个程序的全局作用域,在函数定义中的"sum"的作用域是函数"inc"的局部作用域,在最后一行中的"sum"的作用域是全局作用域。

 

实验任务2

task2_2

list1 = [1, 9, 8, 4]

print(sorted(list1))
print(sorted(list1, reverse=True))
print(sorted(list1, True))

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答:python内置函数sorted()中,参数reverse的传递方式是否必须使用关键字

 task2_3

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))

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 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: float 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:
        t = input('输入一元二次方程系数a b c, 或者,输入#结束: ')
        if t == '#':
            print('结束计算,退出')
            break
        a, b, c = map(float, t.split())
        if a == 0:
            raise ValueError('a = 0, 不是一元二次方程')
    except ValueError as e:
        print(repr(e))
        print()
    except:
        print('有其它错误发生\n')
    else:
        root1, root2 = solve(a, b, c)
        print(f'root1 = {root1:.2f}, root2 = {root2:.2f}')
        print()

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 实验任务4

def list_generator(a,b,c = 1):
    i = a
    lst = []
    while a <= i <= b:
        lst.append(i)
        i += c

    return lst

list1 = list_generator(-5, 5)
print(list1)
list2 = list_generator(-5, 5, 2)
print(list2)
list3 = list_generator(1, 5, 0.5)
print(list3)

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 实验任务5

def is_prime(n):
    import math
    m = 0
    for i in range(2, int(math.sqrt(n)) + 1):
        if n % i == 0:
            m += 1
        else:
            m += 0
    if m != 0:
        result = False
    else:
        result = True
    return result

for i in range(4,21,2):
    for j in range(2,i):
        if is_prime(j) == True:
            k = i - j
            if is_prime(k) == True:
                print(f'{i} = {j} + {k}')
                break

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实验任务6

def encoder(text):
    text1 = ''
    for i in text:
        if 'a' <= i <= 'z':
            c = 97 + (ord(i) + 5 - 97) % 26
            text1 += chr(c)
        elif 'A' <= i <= 'Z':
            c = 65 + (ord(i) + 5 - 65) % 26
            text1 += chr(c)
        else:
            text1 += i
    return text1

def decoder(text):
    text1 = ''
    for i in text:
        if 'a' <= i <= 'z':
            c = 97 + (ord(i) - 5 - 97) % 26
            text1 += chr(c)
        elif 'A' <= i <= 'Z':
            c = 65 + (ord(i) - 5 - 65) % 26
            text1 += chr(c)
        else:
            text1 += i
    return text1

text = input('输入英文文本: ')

encoded_text = encoder(text)
print('编码后的文本: ', encoded_text)

decoded_text = decoder(encoded_text)
print('对编码后的文本解码: ', decoded_text)

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 实验任务7

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

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 实验任务8

def func(n):
    if n == 0:
        return 0
    else:
        return 2*func(n-1) + 1

while True:
    x = input()
    if x == '#':
        print('计算结束')
        break
    n = int(x)
    ans = func(n)
    print(f'n = {n}, ans = {ans}')

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posted @ 2023-05-21 17:37  王欣怡  阅读(26)  评论(0)    收藏  举报