Module:Utils/number

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Contains number-related module utilities.

---

local p = {}

-- Rounds number `num` to `digits` numbers after comma.
function p.round_to_digit(num, digits)
	local str_res = string.format("%." .. digits .. "f", num)
    	:gsub("%.?0+$", "") -- strip trailing zeros (including the dot if theres all zeros after)
    	
    return tonumber(str_res)
end

-- Formats a probability number, ranging from 0 to 1, 
-- to a percentage with specified number of digits after comma.
-- If rounding occurs, also adds "≈".
-- @param prob Probability, from 0 to 1.
-- @param digits Digits after comma. Any more get rounded.
function p.format_probability(prob, digits)
    local percentage = prob * 100

    local percentage_display
    if digits == nil then
        percentage_display = percentage .. "%"
    else
        local percentage_rounded_str = p.round_to_digit(percentage, digits)

        local was_percentage_rounded = tostring(percentage) ~= percentage_rounded_str

        percentage_display = (was_percentage_rounded and "≈" or "") .. percentage_rounded_str .. "%"
    end

    return percentage_display
end

return p