Using nx option when doing zadd in redis-py (redis ver 2.8.4)

Question

I'm using redis 2.8.4 in a python project of mine. In a particular sorted set, I want to zadd with the nx option. The nx option isn't documented in redis-py docs, and according to the docs, it only works with redis 3.0.2 or greater.

So what's an alternative pattern I can follow to simulate the nx option when doing zadd?

Answer 1

I found solution in github issue:

redis.execute_command('ZADD', set_name, 'NX', score, key)

Answer 2

The most efficient pattern that comes to my mind is using using zscore (or zrank) to test for existence. If value exists, do nothing, otherwise, zadd the relevant value.