1.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)
问题：不是。line1中的sum是指Python的内置函数；line3中的sum指的是line2中的全局变量sum；line7中的sum指的是inc函数中的局部变量；line11中的sum指的是line10的全局变量
2.实验任务2
task1
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) )
# 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) )
运行结果如图：
增加print( func2(11, 99, 22, 0, 55, 33))后：
增加print(func3(a=111, b=999, c=222, 0, 555, 333))后：
task2_2
list1 = [1, 9, 8, 4] print( sorted(list1) ) print( sorted(list1, reverse=True) ) print( sorted(list1, True) )
运行结果如图：
task2_2所示情况中，必须使用关键字传递reversse
task2_3
1 def func(a, b, c, /, *, d, e, f): 2 return( [a,b,c,d,e,f] ) 3 4 5 print(func(1,2,3,d = 4,e = 5,f = 6))
3.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
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()
运行结果如图：
加了print(solve.__doc__)后：
4.实验任务4
def list_generator(start,end,step=1):
lst = []
while start <= end:
lst.append(start)
start = start + step
print(lst)
list_generator(-5,5)
list_generator(-5,5,2)
list_generator(1,5,0.5)
运行结果如图：
5.实验任务5
def is_prime(n):
for i in range(2,n+1):
if n % i == 0 or n == 2:
return False
else:
return True
prime_list = []
for n in range(2,21):
if is_prime(n) == True:
prime_list.append(n)
else:
pass
i = 2
while i <= 20:
j = 0
while j < len(prime_list):
k = 0
while k <len(prime_list):
if prime_list[j] + prime_list[k] == i:
print(f'{i} = {prime_list[j]} + {prime_list[k]}')
else:
pass
k += 1
break # 找到后停止该循环
j += 1
i += 2
运行结果如图：
6.实验任务6
# 编码函数encoder()定义
def encoder(text):
text_list = list(text)
for i in range(len(text_list)):
if ord('a') <= ord(text_list[i]) <= ord('z'):
add5 = ord(text_list[i]) + 5
if add5 <= ord('z'):
text_list[i] = chr(add5)
else:
add5 = add5 % ord('z') - 1 +ord('a')
text_list[i] = chr(add5)
elif ord('A') <= ord(text_list[i]) <= ord('Z'):
add5 = ord(text_list[i]) + 5
if add5 <= ord('z'):
text_list[i] = chr(add5)
else:
add5 = add5 % ord('Z') - 1 +ord('A')
text_list[i] = chr(add5)
else:
pass
return ''.join(text_list)
# 解码函数decoder()定义
def decoder(text):
text_list = list(text)
for i in range(len(text_list)):
if ord('a') <= ord(text_list[i]) <= ord('z'):
red5 = ord(text_list[i]) - 5
if ord('a') <= red5:
text_list[i] = chr(red5)
else:
red5 = ord('z') - (ord('a') - red5 - 1)
text_list[i] = chr(red5)
elif ord('A') <= ord(text_list[i]) <= ord('Z'):
red5 = ord(text_list[i]) - 5
if ord('A') <= red5:
text_list[i] = chr(red5)
else:
red5 = ord('Z') - (ord('A') - red5 - 1)
text_list[i] = chr(red5)
else:
pass
return ''.join(text_list)
# 主体代码逻辑
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)
运行结果如图：
7.实验任务7
# collatz函数定义
def collatz(n):
n_list.append(n)
while True:
if n % 2 == 0 and n != 0:
collatz(n // 2)
elif (n + 1) % 2 == 0 and n != 1:
collatz(n * 3 + 1)
elif n == 1:
print(n_list)
break
# 自定义异常
class Error(Exception):
def __init__(self,n):
self.n = n
def __str__(self):
print('Error: must be a positive integer')
# 主题代码逻辑
try:
n_list = []
n = input('输入一个正整数:')
if n.isdigit() == False:
raise Error(n)
elif int(n) <= 0:
raise Error(n)
else:
collatz(int(n))
except Error:
print('Error: must be a positive integer')
8.实验任务8
# 函数func()定义
def func(n):
if n == 1:
ans = 2 - 1
else:
ans = 2 * func(n-1) +1
n -= 1
return ans
#
while True:
x = input()
if x == '#':
print('计算结束')
break
n = int(x)
ans = func(n)
print(f'n = {n}, ans = {ans}')
运行结果如图：
实验总结
作用域：LEGB（局部-嵌套-全句-内置）
参数： * 后面的只能按关键字传递
/前面的只能按位置传递
函数的异常和处理
嵌套：找出f(n)和f(n-1)的关系