L1 = ['Hello', 'World', 18, 'Apple', None]
L2 = [s.lower() for s in L1 if isinstance(s, str)]
# 测试:
print(L2)
if L2 == ['hello', 'world', 'apple']:
print('测试通过!')
else:
print('测试失败!')
['hello', 'world', 'apple']
测试通过!
#斐波拉契函数,max参数表示生成的数列中的元素的个数
def fib(max):
n, a, b = 0, 0, 1
while n < max:
print(b)
a, b = b, a + b
n += 1
return 'done'
fib(6)
1
1
2
3
5
8
'done'
# 用生成器编写斐波拉契函数
def fib(max):
n, a, b = 0, 0, 1
while n < max:
yield b
a, b = b, a + b
n += 1
return 'done'
for x in fib(6):
print(x)
1
1
2
3
5
8
def fib(max):
n, a, b = 0, 0, 1
while n < max:
yield b
a, b = b, a + b
n = n + 1
return 'done'
g = fib(6)
while True:
try:
x = next(g)
print(x)
# 捕捉return值
except StopIteration as e:
print(e.value)
break
1
1
2
3
5
8
done
杨辉三角形生成器
https://blog.csdn.net/zmy_3/article/details/51173580
def triangles():
a = [1]
while True:
yield a
a = [sum(i) for i in zip([0] + a, a + [0])]
# 期待输出:
# [1]
# [1, 1]
# [1, 2, 1]
# [1, 3, 3, 1]
# [1, 4, 6, 4, 1]
# [1, 5, 10, 10, 5, 1]
# [1, 6, 15, 20, 15, 6, 1]
# [1, 7, 21, 35, 35, 21, 7, 1]
# [1, 8, 28, 56, 70, 56, 28, 8, 1]
# [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
n = 0
results = []
for t in triangles():
print(t)
results.append(t)
n = n + 1
if n == 10:
break
if results == [
[1],
[1, 1],
[1, 2, 1],
[1, 3, 3, 1],
[1, 4, 6, 4, 1],
[1, 5, 10, 10, 5, 1],
[1, 6, 15, 20, 15, 6, 1],
[1, 7, 21, 35, 35, 21, 7, 1],
[1, 8, 28, 56, 70, 56, 28, 8, 1],
[1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
]:
print('测试通过!')
else:
print('测试失败!')
[1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]
[1, 5, 10, 10, 5, 1]
[1, 6, 15, 20, 15, 6, 1]
[1, 7, 21, 35, 35, 21, 7, 1]
[1, 8, 28, 56, 70, 56, 28, 8, 1]
[1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
测试通过!