Question

Using the IN operation in a Google App Engine query is limited to 30 items in the list per query, so I have to find a way to break up the list into multiple lists with a maximum of 30 items in each array, and query each sub array.

I’ve come up with a small solution to do this, but it’s very inelegant, and I’m not sure if this is the best way to do this. I’m new to Python, so I’m wondering how I might do this correctly or more elegantly?

I’m querying for User.query(User.email IN emails)

max_length = 30
iter_count = len(emails) / max_length
for i in range(iter_count):         
    min = i  * max_length
    max = (i + 1) * max_length
    if min > len(emails):
       break
    if max > len(emails):
       max = len(emails)

    current_array = emails[min:max]
    # query this array

Answer 1

max_length = 30
for i in xrange(0, len(emails), max_length):
    current_array = emails[i:i+max_length]
    # query this array