[英]Convert decimal to hex in Lua 4?
I found this formula to convert decimal numbers to hexadecimal color values in Lua:我发现这个公式可以在 Lua 中将十进制数转换为十六进制颜色值:
http://lua-users.org/lists/lua-l/2004-09/msg00054.html http://lua-users.org/lists/lua-l/2004-09/msg00054.html
However, I have a few questions about the formula:但是,我对公式有几个问题:
Thanks!!谢谢!!
In Lua 5.x you can use the string.format function with the %x
format specifier to convert integers to their hexadecimal representation.在 Lua 5.x 中,您可以使用带有
%x
格式说明符的 string.format 函数将整数转换为其十六进制表示。 In your case it would look like this:在您的情况下,它看起来像这样:
local input = 0.5
local output = string.format("%x", input * 255) -- "7F"
I don't know Lua 4.0.1 well so I can't tell you if this function is available (perhaps under a different name).我不太了解 Lua 4.0.1,所以我不能告诉你这个功能是否可用(也许用不同的名字)。 That said, if its not, then you might be able to workaround by turning this into a C function that uses
sscanf
.也就是说,如果不是,那么您可以通过将其转换为使用
sscanf
的 C 函数来解决。
The example function demonstrated at http://lua-users.org/lists/lua-l/2004-09/msg00054.html does not converts negative numbers. http://lua-users.org/lists/lua-l/2004-09/msg00054.html中演示的示例函数不会转换负数。 Here is an example of conversion for both, negative and positive numbers:
以下是负数和正数的转换示例:
function decimalToHex(num)
if num == 0 then
return '0'
end
local neg = false
if num < 0 then
neg = true
num = num * -1
end
local hexstr = "0123456789ABCDEF"
local result = ""
while num > 0 do
local n = math.mod(num, 16)
result = string.sub(hexstr, n + 1, n + 1) .. result
num = math.floor(num / 16)
end
if neg then
result = '-' .. result
end
return result
end
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