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生成器对象通过它的next方法返回一个值，直到触发StopIteration异常.
你需要做的只是像创建一个函数一样去创建一个生成器，它包含一个yield语句,pyth
on会认yield并将它标记为生成器。当函数执行到执行到yield语句时，它会像return语句一样返回一个值，唯一不同的是，python解释器会返回一个next函数的栈(stack)指引.
创建一个生成器:
1 def mygenerator(): 2 yield 1 3 yield 2 4 yield ‘a‘ 5 6 """ 7 >>> mygenerator() 8 <generator object mygenerator at 0x00B18EB8> 9 >>> g = mygenerator() 10 >>> next(g) 11 1 12 >>> next(g) 13 2 14 >>> next(g) 15 ‘a‘ 16 >>> next(g) 17 18 Traceback (most recent call last): 19 File "<pyshell#5>", line 1, in <module> 20 next(g) 21 StopIteration 22 >>> 23 ""
1 >>> x = mygenerator() 2 >>> x.next() 3 1 4 >>> x.next() 5 2 6 >>> x.next() 7 ‘a‘ 8 >>> x.next 9 <method-wrapper ‘next‘ of generator object at 0x012EF288> 10 >>> x.next() 11 12 Traceback (most recent call last): 13 File "<pyshell#12>", line 1, in <module> 14 x.next() 15 StopIteration 16 >>>
我们来写一个函数shorten带一个字符列表参数，返回这个列表的缩写值。长度由元音的数量决定。比如loremipsum有四个元音(o,e,i,u)那么下一个返回的缩写将会是前面四个，dolorist-->dolo,这个有两个元音，下一个将返回前面两个字符
1 #coding=utf-8 2 def shorten(string_list): 3 length = len(string_list[0]) 4 5 for s in string_list: 6 length = yield s[:length] 7 8 mystringlist = [‘loremipsum‘, ‘dolorist‘, ‘ametfoobar‘] 9 shortstringlist = shorten(mystringlist) 10 result = [] 11 12 try: 13 s = next(shortstringlist) 14 result.append(s) 15 16 while True: 17 number_of_vovels = len(filter(lambda letter: letter in ‘aeiou‘,s)) 18 19 #下一个缩写的字符 20 #由上一个的字符串的元音多少决定 21 s = shortstringlist.send(number_of_vovels) 22 result.append(s) 23 24 except StopIteration: 25 pass 26 27 28 """ 29 >>> result 30 [‘loremipsum‘, ‘dolo‘, ‘am‘] 31 >>> 32 """
send()方法允许我们传一个值给生成器
标签：style blog color io os ar for sp div
原文地址：http://www.cnblogs.com/jypwn/p/4032056.html
