CODEWITHSUNDEEP
mathluamodulo
Cyclone
Cyclone

Reputation: 15269

Lua replacement for the % operator

I want to check, if a number is divisible by another number:

for i = 1, 100 do
    if i % 2 == 0 then
        print( i .. " is divisible.")
    end
end

This should work without any problems, but with the Lua in my server the script doesn't run if there is a % in the script... I dont know whats the reason, so is there any "replacement" for that? So I could check the number divsibility?

Thank you.

Upvotes: 47

Views: 127337

Answers (6)

Simon Forsberg
Simon Forsberg

Reputation: 13351

Lua 5.0 did not support the % operator.

Lua supports the usual arithmetic operators: the binary + (addition), - (subtraction), * (multiplication), / (division), and ^ (exponentiation); and unary - (negation).

https://www.lua.org/manual/5.0/manual.html

Lua 5.1 however, does support the % operator.

Lua supports the usual arithmetic operators: the binary + (addition), - (subtraction), * (multiplication), / (division), % (modulo), and ^ (exponentiation); and unary - (negation).

https://www.lua.org/manual/5.1/manual.html

If possible, I would recommend that you upgrade. If that is not possible, use math.mod which is listed as one of the Mathematical Functions in 5.0 (It was renamed to math.fmod in Lua 5.1)

Upvotes: 8

Jim Gao
Jim Gao

Reputation: 159

function mod(a, b)
    return a - (math.floor(a/b)*b)
end

Upvotes: 6

vr3C
vr3C

Reputation: 1774

Use math.fmod, accroding lua manual math.mod was renamed to math.fmod in lua 5.1.

Upvotes: 3

lhf
lhf

Reputation: 72342

Use math.fmod(x,y) which does what you want:

Returns the remainder of the division of x by y that rounds the quotient towards zero.

http://www.lua.org/manual/5.2/manual.html#pdf-math.fmod

Upvotes: 59

anonymous
anonymous

Reputation: 61

for i = 1, 100 do
    if (math.mod(i,2) == 0) then
        print( i .. " is divisible.")
    end
end

Upvotes: 5

ninesided
ninesided

Reputation: 23273

It's not ideal, but according to the Lua 5.2 Reference Manual:

a % b == a - math.floor(a/b)*b

Upvotes: 30

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