Lua: print integer as a binary

Question

How can I represent integer as Binary?

so I can print 7 as 111

Answer 1

You write a function to do this.

num=7
function toBits(num)
    -- returns a table of bits, least significant first.
    local t={} -- will contain the bits
    while num>0 do
        rest=math.fmod(num,2)
        t[#t+1]=rest
        num=(num-rest)/2
    end
    return t
end
bits=toBits(num)
print(table.concat(bits))

In Lua 5.2 you've already have bitwise functions which can help you ( bit32 )

---

Here is the most-significant-first version, with optional leading 0 padding to a specified number of bits:

function toBits(num,bits)
    -- returns a table of bits, most significant first.
    bits = bits or math.max(1, select(2, math.frexp(num)))
    local t = {} -- will contain the bits        
    for b = bits, 1, -1 do
        t[b] = math.fmod(num, 2)
        num = math.floor((num - t[b]) / 2)
    end
    return t
end