Formatting Floats with string.format

I wanted to show only 2 positions after the decimal point. To do that I wrote this little piece of code:

print(string.format("2.2f", percentage))

The problem is, that it prints a number like 87.044352 instead of 87.04. I know that I can round it when multiplying by 100, using math.floor and dividing by 100 but string.format is there for a reason :)/>
Is it possible that ComputerCraft doesn't implement this case? It works fine on my Linux lua shell, though.

This sort of format string doesn't exist in Lua. The trouble is %e, %f and %g all do the same thing in computer craft (see here). Your best bet is doing: string.format("%f", percentage):sub(1, 5) instead.

Oops I got a small typo in my code: The % is missing but it exists in LUA:

Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
> percentage = 87.044352
> print(string.format("2.2f", percentage))
2.2f
> print(string.format("%2.2f", percentage))
87.04
>

And it's explained at http://www.lua.org/pil/20.html

You're right that it does exist in Lua, but LuaJ's implementation of the function is broken in this regard. Your best bet is to manually format the string yourself.

local myNumString = tostring(myNum)
if string.match(myNumString, "%.") then
  myNumString = myNumString.."0"
else
  myNumString = myNumString..".00"
end
local myFloatString = string.match(myNumString, "^(%d+%.%d%d)")

You could put this in a function to make it easier to format multiple different numbers.

Thanks :)/>