实验四

1

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，依次为内置作用域，作用于闭包函数外的函数中的作用域（Enclosing，简写为 E），局部作用域，全局作用域

 

 

2—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]

# func1调用：按位置传递、按参数传递都可以
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))
# func2调用：d,e,f必须按关键字传递
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( func2(11, 99, 22, 0, 55, 33) )

# func3调用：a,b,c必须按位置传递
print( func3(111, 999, 222, 0, 555, 333))
print( func3(111, 999, 222, d=0, e=555, f=333) )

 

 

 

 

 

 reserve以key判断

 

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

 

 

 

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))

 

 

 

def solve(a, b, c):
    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()

 

 

 

def list_generator(a,b,c=1):
    l=[a]
    while True:
        if c==None:
            a+=1
            l.append(a)
            if a==b:
                break
        else:
            a+=c
            l.append(a)
            if a==b:
                break
    return l
list1 = list_generator(-5,5)
print(list1)
  
list2 = list_generator(-5,5,2)
print(list2)
  
list3 = list_generator(1,5,0.5)
print(list3)

 

 

from math import sqrt
  
def is_prime(n):
    if n==1 or n==0:
        return False
    for i in range(2,int(sqrt(n)+1)):
        if n%i==0:
            return False
    return True
def gd(x):
    for i in range(2,x):
        if is_prime(i):
            if is_prime(x-i):
                print(x,'=',i,'+',x-i)
                return True
    return False
i=4
while(gd(i) and i<20):
    i+=2

 

 

def encoder(s):
    s=list(s)
    for i in range(len(s)):
        if s[i].isalpha():
            if 'a'<=s[i].lower()<'v':
                s[i]=chr(ord(s[i])+5)
            else:
                s[i]=chr(ord(s[i])-21)
        else:
            s[i]=s[i]
    s=''.join(s)
    return s
def decoder(s):
    s=list(s)
    for i in range(len(s)):
        if s[i].isalpha():
            if 'a'<=s[i].lower()<='e':
                s[i]=chr(ord(s[i])+21)
            elif 'e'<s[i].lower()<='z':
                s[i]=chr(ord(s[i])-5)
        else:
            s[i]=s[i]
    s=''.join(s)
    return s
s=input('输入英文文本: ')
print(f'编码后的文本:{encoder(s)}')
print(f'对编码后的文本解码:{decoder(encoder(s))}')

 

 

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