How to output pairs() in order ?

twisttap

Hello,

I have a multi dimensional tables like below and when I use a for loop to output them with pairs the output I get is not the way I like. Not in a proper order. Is there a way to get a proper output for this ?

TABLES:

recipes = { type1 = { food1 = {name="Food 1", person=4, time=45, calorie=755, id=1}, food2 = {name="Food 2", person=4, time=45, calorie=755, id=2}, food3 = {name="Food 3", person=4, time=45, calorie=755, id=3}, food4 = {name="Food 4", person=4, time=45, calorie=755, id=4}, food5 = {name="Food 5", person=4, time=45, calorie=755, id=5}, food6 = {name="Food 6", person=4, time=45, calorie=755, id=6} }, type2 = { food1 = {name="Food 7", person=4, time=45, calorie=755, id=1}, food2 = {name="Food 8", person=4, time=45, calorie=755, id=2}, food3 = {name="Food 9", person=4, time=45, calorie=755, id=3}, food4 = {name="Food 10", person=4, time=45, calorie=755, id=4}, food5 = {name="Food 11", person=4, time=45, calorie=755, id=5}, food6 = {name="Food 12", person=4, time=45, calorie=755, id=6} } }

CODE TO OUTPUT:

for k,v in pairs(recipes) do for i,j in pairs(v) do print(j.name, j.person, j.calorie, j.time, j.id) end     end

-- Print Output below --

1 Food 1 4 755 45 1 Food 6 4 755 45 6 Food 3 4 755 45 3 Food 2 4 755 45 2 Food 5 4 755 45 5 Food 4 4 755 45 4 2 Food 7 4 755 45 1 Food 12 4 755 45 6 Food 9 4 755 45 3 Food 8 4 755 45 2 Food 11 4 755 45 5 Food 10 4 755 45 4

atilim

You can use arrays:

recipes = { { {name="Food 1", person=4, time=45, calorie=755, id=1}, {name="Food 2", person=4, time=45, calorie=755, id=2}, {name="Food 3", person=4, time=45, calorie=755, id=3}, {name="Food 4", person=4, time=45, calorie=755, id=4}, {name="Food 5", person=4, time=45, calorie=755, id=5}, {name="Food 6", person=4, time=45, calorie=755, id=6} }, { {name="Food 7", person=4, time=45, calorie=755, id=1}, {name="Food 8", person=4, time=45, calorie=755, id=2}, {name="Food 9", person=4, time=45, calorie=755, id=3}, {name="Food 10", person=4, time=45, calorie=755, id=4}, {name="Food 11", person=4, time=45, calorie=755, id=5}, {name="Food 12", person=4, time=45, calorie=755, id=6} } }

and ipairs instead of pairs:

for k,v in ipairs(recipes) do for i,j in ipairs(v) do print(j.name, j.person, j.calorie, j.time, j.id) end end

note: btw, using the length operator (#) is more efficient than ipairs

ar2rsawseen

Completely agree to what @atilim says.

BTW in javascript there is a standard optimization where you cache length in a variable and reuse it and not getting length on every iteration of the loop. Does the same apply to lua?
Is there a difference in performance between:

for i = 1, i < #obj do   end

and

local l = #obj for i = 1, i < l do   end

?

atilim

Reference manual http://www.lua.org/manual/5.1/manual.html#2.4.5 says that: All three control expressions are evaluated only once, before the loop starts.

It seems they are same in Lua.

twisttap

Thanks for replies, using an array did the work for me.