Python字典生成式、集合生成式、生成器用法实例分析

#d = {key: value for (key, value) in iterable}
d1 = {'x': 1, 'y': 2, 'z': 3}
d2 = {k: v for (k, v) in d1.items()}
print(d2)

s1={x for x in range(10)}
print(s1)

print("-----使用()列表生成式生成generator------")
g=(x*x for x in range(10))
print(type(g),g)
print(next(g),next(g),next(g))

print("\n----使用yield生成generator-------")
def ge():
  print("第一次yield")
  yield 1
  print("第二次yield")
  yield 2
  print("第三次yield")
  yield 3
o = ge()
print(next(o))
print(next(o))
print(next(o))

def fib(max):
  n,a,b = 0,0,1
  while n <max:
    yield b
    a,b =b,a+b
    n = n+1
  return 'done'

print("\n-----尝试获得函数返回值------")
gg=fib(6)
while True:
  try:
    x=next(gg)
    print("g:",x)
  except StopIteration as e:
    print('返回值等于:',e.value)
    break

def ge():
  print("第一次yield")
  yield 1
  print("第二次yield")
  yield 2
  print("第三次yield")
  yield 3
o = ge()

print("\n---迭代generator的方法--------")
for x in o:
  print(x)#相当于进入到generator函数中，执行下去并得到返回值