"The most standard Lua tables are "sequence" where the key are natural numbers starting from 1, but Wikibase tables seem to have a key "0". It is a bit annoying. According to the documentation, "Many Lua functions operate only on sequences, and ignore non-positive-integer keys." For instance, the number of claims for a property, as given by #entity.claims.pXX is one less than expected. --Zolo (talk) 09:49, 19 September 2013 (UTC)"