实验4

print(sum)

sum=42

print(sum)

def inc(n):
   sum=n+1
   print(sum)
   return sum
sum=inc(7)+inc(7)
print(sum)

实验结果：

 

 

不代表同一变量名.

一：内置作用域 二：全局作用域 三：局部作用域 四：全局作用域

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(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))
 # 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))

运行结果：

 

 

 

 

 

 

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

运行结果：

 

 参数reverse的传递方式必须使用关键字传递

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))

运行结果：

 

 

def solve(a,b,c):
     '''
     求解一元二次方程，返回方程的两个根
     :param 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


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()

运行结果：

 

 

 

 加一行代码

print(solve.__doc__)

运行结果：

 

 

def list_generator(x,y,step=1):
      list4=[]
      while x<=y:
          list4.append(x)
          x+=step
      return list4
list1=list_generator(-5, 5)
print(list1)
list2=list_generator(-5, 5, 2)
print(list2)
list3=list_generator(1, 5, 0.5)
print(list3)

运行结果：

 

def is_prime(x):
      if x<=1:
          return False
      for i in range(2, int(x**0.5)+1):
        if x % i==0 :
              return False
      else:
          return True


for y in range(2,21,2):
     for j in range(2,y):
         if is_prime(y-j) and is_prime(j):
             print(f'{y}={j}+{y-j}')

运行结果：

 

 

def encoder(s):
    ls = []
    for i in s:
        x = ord(i)
        if (x>=97 and x<=117) or (x>=65 and x<=85):
            ls.append(chr(x+5))
        if (x>=86 and x<=90) or (x>=118 and x<=122):
            ls.append(chr(x-21))
        if  x<65 or x>122:
            ls.append(chr(x))
    return ''.join(ls)
def decoder(s):
    ls = []
    for i in s:
        x = ord(i)
        if (x >= 102 and x <= 122) or (x >= 70 and x <= 90):
            ls.append(chr(x - 5))
        if (x >= 65 and x <= 69) or (x >= 97 and x <= 101):
            ls.append(chr(x+21))
        if x < 65 or x > 122:
            ls.append(chr(x))
    return ''.join(ls)
x = input('输入英文文本: ')
s = encoder(x)
print(f'编码后的文本：{s}')
print(f'对编码后的文本解码:{decoder(s)}')

运行结果：

 

 

def collatz(n):
    if n%2 == 0:
        return n/2
    elif n%2!=0:
        return n*3+1
while True:
    l = []
    try:
        x = eval(input('enter a positive integer:'))
        if type(x) is not int or x <= 0:
            raise NameError
    except NameError:
        print('Error:must be a positive integer')
    else:
        while x>1:
            l.append(x)
            x = collatz(x)
        l.append(x)
        print(l)

运行结果：