On Mon, Jan 25, 2016 at 5:22 PM Steven D'Aprano <steve@pearwood.info> wrote:

# Still a toy, but perhaps a bit more of a realistic toy.
searchers = []
for provider in search_provider:
key = API_KEYS[provider]
url = SEARCH_URLS[provider]
def lookup(*terms):
terms = "/q=" + "+".join(escape(t) for t in terms)
u = url + ("key=%s" % key) + terms
return fetch(u) or []
searchers.append(lookup)

I'd define the basic function outside the loop.

def lookup(root_url, api_key, *terms):

args = root_url, api_key, "+".join(escape(t) for t in terms)

url = '%s?key=%s&q=%s' % args

return fetch(url) or []

Then use ``functools.partial`` inside the loop to create the closure.

searchers = []

for provider in search_provider:

key = API_KEYS[provider]

url = SEARCH_URLS[provider]

searchers.append(partial(lookup, url, key))

Or even more concisely, you could use a comprehension at that point.

searchers = [partial(lookup, SEARCH_URLS[p], API_KEYS[p]) for p in search_provider]