What does "for i, v in ipairs do" mean?

[LaserGuns]

I don't think that's exactly how its used, but I see "for blah blah in ipairs do" in a lot of code and I think it would be useful.
What does the for/do loop do?
What are ipairs? How do they work?

[Roland_Yonaba]

Sometimes, for some reasons, you need to loop trhough a collection of elements.
For loop is meant for that purpose.

Code: Select all

t = { 'a','b','c','d'}
for i = 1, #t do 
   print(i,t[i])
end

will output

1, 'a'
2, 'b'
3, 'c'
4, 'd'

pairs/ipairs are iterators.
They offers better support to loop trough a table.

Code: Select all

t = { 'a','b','c','d'}
for key,value in ipairs(t) do 
   print(key,value)
end

will have the same output as before.
Pairs will also act the same way, and have the same output.

Sometimes, values are not indexed with numeric keys, in a table.
In this case, ipairs won't work, but pairs will.

Code: Select all

t = {}
t.x = 1
t.y = 2
t.z = 3
for key,value in pairs(t) do 
   print(key,value)
end

will output

"x",1
"y",2
"z",3

That's a basic example. You will find more intel here :
Lua_Tables_Tutorial
Pairs/ipairs

There's an online interpreter for Lua here, you can try some snippets there to understand.

[LaserGuns]

Alright. Thanks!