blocks|key|1337811|text|迭代器函数的返回值用作终止时引发的StopIteration的参数：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1337812|>>>+it+=+gen_test()
>>>+next(it)
0
>>>+next(it)
1
>>>+next(it)
2
>>>+next(it)
3
>>>+next(it)
4
>>>+next(it)
5
>>>+next(it)
Traceback+(most+recent+call+last):
++File+"<stdin>",+line+1,+in+<module>
StopIteration:+[0,+1,+2,+3,+4,+5]|code-block|syntax|javascript|1337813|只有第一个StopIteration获取指定值。进一步尝试迭代空生成器将引发空异常：|1337814|>>>+next(it)
Traceback+(most+recent+call+last):
++File+"<stdin>",+line+1,+in+<module>
StopIteration|1337815|您可以通过避免for循环并自己捕获异常来从迭代器的正常运行中提取返回值：|1337816|it+=+gen_test()
while+True:
++++try:
++++++++x+=+next(it)
++++++++#+Do+the+stuff+you+would+normally+do+in+a+for+loop+here
++++except+StopIteration+as+e:
++++++++ret+=+e.value
++++++++break
print(ret)|1337817|考虑到您必须在不使用for循环和无法返回积累的数据之间做出选择，所有这些都是一种笨拙的方法。假设你不能尝试在外部积累数据(例如，只做list(gen_test()))，你可以通过使用一个类来使你的生成器的状态可以公开访问：|1337818|class+gen_test:
++++def+__init__(self):
++++++++self.l+=+[]
++++++++self.it+=+iter(range(6))

++++def+__iter__(self):
++++++++return+self

++++def+__next__(self):
++++++++i+=+next(self.it)
++++++++self.l.append(i)
++++++++return+i|1337819|现在你可以这样做了|1337820|>>>+it+=+gen_test()
>>>+for+x+in+it:
...+++++print(x)
0
1
2
3
4
5
>>>+print(it.l)
[0,+1,+2,+3,+4,+5]|1337821|entityMap^0|H|D|0|0|5|D|0|0|7|3|0|0|A|3|1U|G|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|U|3|V|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|W|3|X|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|H|7|1L|8|@]|D|@]|E|$I|J]]|$1|10|3|-4|5|6|7|1M|8|@]|D|@]|E|$]]]|11|$]]

The return value of your iterator function is used as the argument to the <code>StopIteration</code> that it raises when it terminates:
<pre><code>&gt;&gt;&gt; it = gen_test()
&gt;&gt;&gt; next(it)
0
&gt;&gt;&gt; next(it)
1
&gt;&gt;&gt; next(it)
2
&gt;&gt;&gt; next(it)
3
&gt;&gt;&gt; next(it)
4
&gt;&gt;&gt; next(it)
5
&gt;&gt;&gt; next(it)
Traceback (most recent call last):
 File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
StopIteration: [0, 1, 2, 3, 4, 5]
</code></pre>
Only the first <code>StopIteration</code> gets the specified value. Further attempts to iterate an empty generator will raise an empty exception:
<pre><code>&gt;&gt;&gt; next(it)
Traceback (most recent call last):
 File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
StopIteration
</code></pre>
You can extract the return value from a normal run of the iterator by avoiding <code>for</code> loops and trapping the exception yourself:
<pre><code>it = gen_test()
while True:
 try:
 x = next(it)
 # Do the stuff you would normally do in a for loop here
 except StopIteration as e:
 ret = e.value
 break
print(ret)
</code></pre>
All this is an awkward approach given that you have to decide between not using <code>for</code> loops and not being able to return your accumulated data. Assuming that you're not OK with trying to accumulate the data externally (e.g. just doing <code>list(gen_test())</code>), you can make your generator's state publicly accessible by using a class:
<pre><code>class gen_test:
 def __init__(self):
 self.l = []
 self.it = iter(range(6))

 def __iter__(self):
 return self

 def __next__(self):
 i = next(self.it)
 self.l.append(i)
 return i
</code></pre>
Now you can do something like
<pre><code>&gt;&gt;&gt; it = gen_test()
&gt;&gt;&gt; for x in it:
... print(x)
0
1
2
3
4
5
&gt;&gt;&gt; print(it.l)
[0, 1, 2, 3, 4, 5]
</code></pre>

blocks|key|5267744|text|在您的函数中出现yield会使其不同于常规函数-+python将其称为generator。您不能调用一个生成器并期望它像一个函数一样执行。可能在退化或简单化的情况下除外。要在生成器生命周期结束时检索问题中的状态信息(如整个列表l+)，需要将其存储在变量中或每次在yield语句中返回它。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5267745|要在每次调用生成器时返回它，请执行以下操作：|5267746|def+gen_test():
++++l+=+[]
++++for+i+in+range(6):
++++++++l.append(i)
++++++++yield+i,+l
++++
for+y,l+in+gen_test():
++++++++print+(y,l)|code-block|syntax|javascript|5267747|否则，您可以将生成器声明为类的一部分，并将中间结果存储在类变量中。然后稍后使用不同的调用检索该变量值。|5267748|entityMap^0|8|5|Z|9|35|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|P|$]]

The presence of <code>yield</code> in your function turns it into something different than a regular function - python calls it a <code>generator</code>. You can not call a generator and expect it to preform like a function. Except perhaps in a degenerate or simplistic case.
To retrieve state information ( like the whole list <code>l</code> ) in your question at the end of the generator life, you need to store in in a variable or return it every time in the yield statement.
To return it every time the generator is called do this:
<pre><code>def gen_test():
 l = []
 for i in range(6):
 l.append(i)
 yield i, l
 
for y,l in gen_test():
 print (y,l)
 
</code></pre>
Otherwise you could declare your generator as part of a class and store intermediate results in a class variable. Then retrieve that variable value using a different call later.

blocks|key|1337850|text|不能在生成器函数(包含yield的函数)中使用return返回表达式，因为调用该函数会返回生成器。生成器中的return与引发StopIteration相同，如果您返回一个值，则该值将被填充到ecxeption中。由于Python中的大多数迭代方法都不能让您访问StopIteration，因此很难获得这个值，除非您避免使用for和大多数其他迭代方法(例如list())。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1337851|你可以用你想要的返回值引发一个异常：|1337852|class+ReturnValue(Exception):
++++pass

def+gen_test():
++++l+=+[]
++++for+i+in+range(6):
++++++++l.append(i)
++++++++yield+i
++++raise+ReturnValue(l)

try:
++++for+x+in+gen_test():
++++++++print(x)
except+ReturnValue+as+e:
++++print(e.args[0])++#+or
++++returnvalue+=+e.args[0]
++++#+note:+variable+e+goes+away+after+exception+handler|code-block|syntax|javascript|1337853|不过，这看起来像是一次黑客攻击。类可能更好：|1337854|class+GenTest:
++++value+=+None
++++def+__iter__(self):
++++++++l+=+[]
++++++++for+i+in+range(6):
++++++++++++l.append(i)
++++++++++++yield+i
++++++++self.value+=+l

for+x+in+(it+:=+GenTest()):
++++print(x)

print(it.value)|1337855|entityMap^0|B|5|N|6|1I|6|1R|D|3N|D|4I|3|4Y|6|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|19|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1A|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|R|$]]

You can't easily use <code>return</code> in a generator function (a function that contains <code>yield</code>) to return an expression, because calling the function returns a generator. <code>return</code> in a generator is the same as raising <code>StopIteration</code> and if you return a value, that gets stuffed into the ecxeption. Since most ways of iterating in Python don't give you access to the <code>StopIteration</code>, this value is difficult to get at, unless you eschew <code>for</code> and most other ways to iterate (e.g. <code>list()</code>).
You could raise an exception with your desired return value:
<pre><code>class ReturnValue(Exception):
 pass

def gen_test():
 l = []
 for i in range(6):
 l.append(i)
 yield i
 raise ReturnValue(l)

try:
 for x in gen_test():
 print(x)
except ReturnValue as e:
 print(e.args[0]) # or
 returnvalue = e.args[0]
 # note: variable e goes away after exception handler
</code></pre>
This seems like a hack, though. A class might be better:
<pre><code>class GenTest:
 value = None
 def __iter__(self):
 l = []
 for i in range(6):
 l.append(i)
 yield i
 self.value = l

for x in (it := GenTest()):
 print(x)

print(it.value)
</code></pre>

blocks|key|1337875|text|好了，这样如何？不要从你的生成器return，产生列表值l作为你最后的控制返回。这样，你就可以避免人们建议的所有Python卷积，只需继续你的一天。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1337876|你可以随时测试生成器的返回类型，看看它是否是一个列表。在Python中，这被认为是完全有效的。|1337877|def+gen_test():
++++l+=+[]
++++for+i+in+range(6):
++++++++l.append(i)
++++++++yield+i
++++yield+l

for+y+in+gen_test():
++++if+isinstance(+y,+type([])):
++++++++print("List+is+",+y)
++++else:
++++++++print+(y)|code-block|syntax|javascript|1337878|entityMap^0|G|6|S|1|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Ok, how about this. Don't <code>return</code> from your generator, yield the list value <code>l</code> as your last return of control. This way you can avoid all the Python convolutions that people will suggest and just get on with your day.
You can always test the return type of the generator to see if its a list. That's considered perfectly valid, in Python.
<pre><code>def gen_test():
 l = []
 for i in range(6):
 l.append(i)
 yield i
 yield l

for y in gen_test():
 if isinstance( y, type([])):
 print(&quot;List is &quot;, y)
 else:
 print (y)
 
</code></pre>

I would like to know how to get the return value of a function after all the execution of yield in a function like this:
<pre><code>def gen_test():
 l = []
 for i in range(6):
 l.append(i)
 yield i
 # i want to know this value after all iteration of yield
 return l
</code></pre>

Getting the value of a return after a yield in python

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我想知道如何在像下面这样的函数中执行完like之后获得函数的返回值：def gen_test():    l = []    for i in range(6):        l.append(i)        yield i    # i want to know this value after all ite...

问在python中获取收益后的返回值
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