When Is It Better To Use A for in pairs loop, vs a regular for loop?

What Wicked said was incorrect, you can loop through a table with a normal for-loop like this:

table = {"one", "two", "three"}

for i = 1, #table, 1 do
print(table[i])
end

Which would print out:

one
two
three

To answer your question:

The difference between a numeric for loop and a pairs for loop is that a pairs for loop only accepts arrays.

When using a numeric for loop to iterate through a table, it would only give you the index, and you'll have to manually fetch the value from the table using the index, but when using a pairs for loop it would directly give you both the index and the value for that index, like so:

local myTable = {"hello", "my", "dude"}

--Numeric for loop
for i = 1, #myTable do
    print("Index "..i.." is assigned the value "..myTable[i])
end

--Pairs for loop
for i, v in pairs(myTable) do
    print("Index "..i.." is assigned the value "..v)

There's also another thing: a numeric for loop takes less time to run than a pairs for loop.

A simple script would prove this:

myTable = {"one", "two", "three"}

local duration1 = tick()

--Pairs for loop
for i, v in pairs(myTable) do
    print(i)
end

duration1 = tick() - duration1
print("The pairs for loop took "..duration1.." seconds to loop")

local duration2 = tick()

--Numeric for loop
for i = 1, #myTable, 1 do
    print(myTable[i])
end

duration2 = tick() - duration2
print("The numeric for loop took "..duration2.." seconds to loop")

Which would output the following:

one
two
three
The pairs for loop took 0.0014321804046631 seconds to loop
one
two
three
The numeric for loop took 0.0012853145599365 seconds to loop

(The normal for-loop and the in-pairs loop were both tested in two separate scripts, but I merged them together here)

See the difference?

Another example here, the exact same test was conducted, but both of the loops iterated through a folder containing three Parts inside of Workspace

These were the results:

Part (x3)
The pairs for loop took 0.0021255016326904 seconds to loop
Part (x3)
The numeric for loop took 0.0017952919006348 seconds to loop

Conclusion

A numeric for loop should be used when iterating through a range of numbers and a pairs loop would be more convenient when iterating through a table, as it gives you both the index and the value. A numeric for loop is also helpful when time is important.

(I encourage you to research more about this.)

First of all, hope this helps and you will get better at Lua.

The difference between a for in pairs loop and a normal for loop is that a pairs loop can additionally loop through a table or an array table while a normal for loop cannot. Please mark as answered for this answer if this helped! That will be amazing!

I use normal for loops when I need to repeat something a # of times. I use pairs/ipairs loops when I need to scan an array or table for whatever reason.

Check out these examples:

Normal: lua for i = 1, 10 do -- Make 10 parts local Part = Instance.new("Part") Part.Parent = workspace end

Pairs: lua for _, Object in pairs(workspace:GetChildren()) do -- Destroy all parts in the workspace if Object:IsA("Part") then Object:Destory() end end

Hope this helps.

Patch