实验四

Task1:

print(sum)
sum = 42
print(sum)
def inc(n):
    sum = n+1
    print(sum)
    return sum
sum = inc(7) + inc(7)
print(sum)
#不是；line1、3、11是全局作用域。line7是函数作用域。

不代表一个变量名；line1、3、11是全局作用域。line7是函数作用域。

Task2_2:

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

是, 需要，理性的，中肯的，正确的，一针见血了。

Task2_3:

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

Task3:

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()

Task4:

# list_generator()函数定义
# 待补足
# ×××
def list_generator(a, b, c = 1):
    list = []
    n = a
    while(n <= 5):
        list.append(n)
        n = n + c
    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:

def isPrime(x):
    if(x == 1):
        return False
    else:
        for i in range(2,x):
            if(x % i == 0):
                return False
                break
        else:
            return True

oushu = [i for i in range(4, 2100, 2)]
sushu = []
for i in range(1, max(oushu)):

    if(isPrime(i) == True):
        sushu.append(i)

for n in oushu:
    for i in range(len(sushu)):
        for j in range(len(sushu)):
            if(n == sushu[i] + sushu[j]):
                print('{} = {} + {}'.format(n, sushu[i], sushu[j]))
                break
        if(n == sushu[i] + sushu[j]):
            break

Task6:

def encoder(x):
    x = list(x)
    for i in range(len(x)):

        if('z' >= x[i].lower() >= 'v'):
            x[i] = chr(ord(x[i]) - 21)
        elif('v' > x[i].lower() >= 'a'):
            x[i] = chr(ord(x[i]) + 5)

    x = ''.join(x)
    return x

def decoder(x):
    x = list(x)
    for i in range(len(x)):

        if('a' <= x[i].lower() <= 'e'):
            x[i] = chr(ord(x[i]) + 21)
        elif('e' < x[i].lower() <= 'z'):
            x[i] = chr(ord(x[i]) - 5)

    x = ''.join(x)
    return x

wenben = input('输入英文文本；')
print('编码后的文本：{}'.format(encoder(wenben)))
print('对编码后的文本解码：{}'.format(decoder(encoder(wenben))))

Task7:

def collatz(x):
    if(x % 2 == 0):
        x = int(x / 2)
    else:
        x = 3 * x + 1
    return x

list = []

try:
    n = eval(input('Enter a positive integer: '))

    if(n <= 0):
        raise
    elif(int(n) != n):
        raise

    while True:
        if(n == 1):
            list.append(n)
            break
        else:
            list.append(int(n))
            n = collatz(n)

    print(list)

except:
    print('Error: must be a positive integer')

 

 

总结：

1.实验很棒，我很喜欢。