Python Returning Data when None expected

Question

I'm using the praw reddit library to pull data from reddit and I ran into this bit of code that I don't understand why it returns any data (inside the class BaseReddit (full source): ``` def get_content(self, page_url, limit=0, url_data=None, place_holder=None, root_field='data', thing_field='children', after_field='after'): """A generator method to return reddit content from a URL. Starts at the initial page_url, and fetches content using the `after` JSON data until `limit` entries have been fetched, or the `place_holder` has been reached. :param page_url: the url to start fetching content from :param limit: the maximum number of content entries to fetch. If limit <= 0, fetch the default_content_limit for the site. If None, then fetch unlimited entries--this would be used in conjunction with the place_holder param. :param url_data: dictionary containing extra GET data to put in the url :param place_holder: if not None, the method will fetch `limit` content, stopping if it finds conte…

Accepted Answer

This is a generator function, which you can tell by the `yield` statement. The value is effectively 'returned' without actually returning from the function. When another value is requested from the function, the generator resumes from the point it yielded (as per the code below, continuing the `for thing` loop...).

```
for thing in root[thing_field]:
    yield thing
```

Simple example:

```
def blah():
    for i in xrange(5):
        yield i + 3

numbers = blah()
print next(numbers)
# lots of other code here...
# now we need the next value
print next(numbers)
```

Python Returning Data when None expected

Solution

Problem