实验4 函数与异常处理应用编程

实验1

print(sum)
sum=42
print(sum)

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

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

Ans: 这里的sum不是一个变量名

line1:内置作用域 line2:全局作用域 line3:局部作用域 line4:全局作用域

实验2

task2_1

def func1(a, b, c, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    默认，参数按位置传递; 也支持关键字传递
    '''
    return [a,b,c,d,e,f]

def func2(a, b, c,*, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    *后面的参数只能按关键字传递
    '''
    return [a,b,c,d,e,f]

def func3(a, b, c, /, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    /前面的参数只能按位置传递
    '''
    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) )

task2_2

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

是的，需要用关键字传递。

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))

 

实验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()

 

实验4

def list_generator(a,b,c=1):
    list1=[a]
    x=a
    while x+c<=b:
        x+=c
        list1.append(x)
    return list1
    
list1 = list_generator(-5, 5)
print(list1)
list2 = list_generator(-5, 5, 2)
print(list2)
list3 = list_generator(1, 5, 0.5)
print(list3)

 

实验5

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

list1=[]
for i in range (2,21):
    if is_prime(i)==True:
        list1.append(i)

for i in range(4,21,2):

    
    for j in list1:
        if is_prime(i-j)==True:
            print(f'{i}={j}+{i-j}')
            break

 

实验6

list_s=['a','b','c','d','e','f','g','h','i','j','k',
        'l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
list_b=['A','B','C','D','E','F','G','H','I','J','K',
        'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']
def encoder(x):
    re=[]
    for i in str(x):
        if i in list_s:
            a=list_s.index(i)
            if a<=20:
                i=list_s[a+5]
                re.append(i)
            else:
                i=list_s[a+5-26]
                re.append(i)
        elif i in list_b:
            a=list_b.index(i)
            if a<=20:
                i=list_b[a+5]
                re.append(i)
            else:
                i=list_b[a+5-26]
                re.append(i)
        else:
            re.append(i)
    re=''.join(re)
    return re
def decoder(x):
    re=[]
    for i in str(x):
        if i in list_s:
            a=list_s.index(i)
            if a>=5:
                i=list_s[a-5]
                re.append(i)
            else:
                i=list_s[a+26-5]
                re.append(i)
        elif i in list_b:
            a=list_b.index(i)
            if a>=5:
                i=list_b[a-5]
                re.append(i)
            else:
                i=list_b[a+26-5]
                re.append(i)
        else:
            re.append(i)
    re=''.join(re)
    return re

x=input('输入英文文本:')
print(f'编码后的文本:{encoder(x)}')
y=encoder(x)
print(f'对编码后的文本解码:{decoder(y)}')

 

 

实验7

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