python生成器和各种推导式

 1 def func():
 2     print(\'我叫周润发\')
 3     yield \'林志玲\'  # yield表示返回. 不会终止函数的执行
 4     print(\'我干嘛了?\')
 5     yield \'宝宝回来了\'
 6     print(\'宝宝你在干嘛\')
 7     yield \'没了\'
 8 ret = func()  # 执行函数,此时没有运行函数
 9 # 此时我们拿到的是生成器
10 print(\'返回值是\', ret)  #<generator生成器   func at 0x0000018DAC980EB8>
11 
12 # 执行到下一个yield
13 print(ret.__next__())  #第一次执行到__next__此时函数才开始执行
14 print(ret.__next__())  #执行到下一个yield
15 print(ret.__next__())  # StopIteration

1 lst = [\'python%s期\' % i for i in range(1, 19)]
2 print(lst)

1 dic = {\"主食\": \"炒面\", \"副食\": \"小拌菜\", \"汤\": \"疙瘩汤\"}
2 dic1 = {v: k for k, v in dic.items()}
3 print(dic1)

 1 g = (i for i in range(10))  # 生成器表达式
 2 
 3 print(g)  # <generator   <genexpr> at 0x000001C354050EB8>
 4 
 5 print(g.__next__())  # 0
 6 print(g.__next__())  # 1
 7 print(g.__next__())  # 2
 8 print(g.__next__())  # 3
 9 print(g.__next__())  # 4
10 print(g.__next__())  # 5
11 print(g.__next__())  # 6
12 print(g.__next__())  # 7
13 print(g.__next__())  # 8
14 print(g.__next__())  # 9

def func():
    lst = [\'衣服%s\' %i for i in range(500)]
    yield from lst  # 可以吧一个可迭代对象

gen = func()
print(gen.__next__())
print(gen.__next__())
print(gen.__next__())