Using KEYS and ARGV with Redis

We have already been using the keys and optional arguments that are accessible as the KEYS and ARGV Lua tables in our Lua server-side scripts in Redis. To illustrate this, we'll run ninth_script that echoes back a Lua table with the KEYS and ARGS variables as members to the Redis client:

>>> ninth_script = """--[[ Returns all KEYS and ARGV as members of a Lua Table ]]--
return {KEYS[1], KEYS[2], ARGV[1], ARGV[2]}"""
>>> keys_and_args = ["Airline:1", "Airline:2", "Singapore Airlines", "Southwest"]
>>> datastore.eval(ninth_script, 2, *keys_and_args)
[b'Airline:1', b'Airline:2', b'Singapore Airlines', b'Southwest']

We can refactor this script—now called tenth_script—so that instead of requiring explicit keys for the Lua table, we can create a for loop that iterates through all of the values in KEYS and ARGV...