In a lua for loop what is a # used for?

Question

I know how for loops work and I use them quite often but also seem to often come across a # in others' code and I want to know what it is for and how to use it. An example of this would be:

for i = 1, #npc do local v = npc[i]

I cant seem to find anything online regarding this, maybe my searches just aren't good but it would be nice if someone could explain it for me, thanks.

Answer 1

In Lua, # is the length operator. for i = 1, #npc essentially loops from 1 to the length of the npc array.

Answer 2

As was already pointed out, it gets the length of a list. However, there's another thing worth pointing out: that for loop is suboptimal and unidiomatic. It would be better written as for i, v in ipairs(npc) do . In general, using # in a for loop is almost always the wrong thing to do.