python yield关键词案例测试

#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'shouke'
def fab(max):
  n, a, b = 0, 0, 1
  result = []
  while n < max:
    result.append(b)
    a, b = b, a + b
    n = n + 1
  return result
for n in fab(5):
  print(n)

def fab(max):
  n, a, b = 0, 0, 1
  while n < max:
    yield b   # 使用 yield
    a, b = b, a + b
    n = n + 1
for n in fab(5):
  print(n)

#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'shouke'
def read_file(fpath):
  BLOCK_SIZE = 1024
  with open(fpath, 'rb') as f:
    while True:
      block = f.read(BLOCK_SIZE)
      if block:
        yield block
      else:
        return
with open('D:\Downloads\\channels-2.1.7-copy.tar.gz', 'wb') as f:
  for data in read_file('D:\Downloads\\channels-2.1.7.tar.gz'):
    f.write(data)