通过谷歌应用引擎和python中的列表进行分页

Question

i have a list. (the list comes from a database query that is stored in memcache, ideally i will not query the database again.)

x = [thing1, thing2, thing3, ... thing100]

i'm using this function to generate the first 10 items in the list at a time.

def grouper(page_size, iterable):
        page = []
    for item in iterable:
        page.append(item)
        if len(page) == page_size:
            yield page
            page = []
    yield page

i'm calling the function

group = grouper(10, x)

i submit my result to my html like so

self.render("index.html", x-items = group.next())

in jinja2 i'm iterating through the group.next() and it correctly displays the first 10 items in the list.

my question is, what code do i put in my html('next' link) to get it it to run the function again, and display the next 10 items?

Answer 1

When you query the database and you need paging, you use cursors. Both the datastore and NDB support cursors. So there is no need to save the query first in memcache.

But if you need to store it first in memcache, you can use your own cursor. See also this blog post from Nick Johnson: http://blog.notdot.net/2010/02/New-features-in-1-3-1-prerelease-Cursors