Python yield 详解（二）

实验了几个小时的yield，附上一段代码：

# encoding: utf-8
from collections import defaultdict, namedtuple

def dataFromFile(fname, sep='\t'):
file_iter = open(fname, 'rU')
for line in file_iter:
line = line.strip().rstrip(sep) # Remove trailing comma
if len(line) < 1 :
continue

record = frozenset(line.split(sep))
yield record
def count(inFile):
items = defaultdict(lambda: 0)
processed_transactions = []
filecount = [0]
filecount[0] = 0
for transaction in inFile:
filecount[0] += 1
processed = []
for item in transaction:
items[item] += 1
processed.append(item)
processed_transactions.append(processed)
print processed_transactions
print "b"
for i in processed_transactions:
yield i
print "c"

if __name__ == '__main__':
inFile = dataFromFile("test", "\t")
for i in count(inFile):
print i
print "a"
test中内容：
f       a       c       d       g       i       m       p

a       b       c       f       l       m       o

b       f       h       j       o

b       c       k       s       p

a       f       c       e       l       p       m       n

执行结果为：

[['a', 'c', 'd', 'g', 'f', 'i', 'm', 'p'], ['a', 'c', 'b', 'f', 'm', 'l', 'o'], ['h', 'b', 'j', 'o', 'f'], ['s', 'c', 'b', 'k', 'p'], ['a', 'c', 'e', 'f', 'm', 'l', 'n', 'p']]

b

['a', 'c', 'd', 'g', 'f', 'i', 'm', 'p']

a

c

['a', 'c', 'b', 'f', 'm', 'l', 'o']

a

c

['h', 'b', 'j', 'o', 'f']

a

c

['s', 'c', 'b', 'k', 'p']

a

c

['a', 'c', 'e', 'f', 'm', 'l', 'n', 'p']

a

c