Module:Formatnum

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This module provides a number formatting function. This function can be used from #invoke or from other Lua modules.

This module is used by Module:Complex date

Use from other Lua modules

To use the module from normal wiki pages, no special preparation is needed. If you are using the module from another Lua module, first you need to load it, like this:

local mf = require('Module:Formatnum')

(The mf variable stands for Module Formatnum; you can choose something more descriptive if you prefer.)

Most functions in the module have a version for Lua and a version for #invoke. It is possible to use the #invoke functions from other Lua modules, but using the Lua functions has the advantage that you do not need to access a Lua frame object. Lua functions are preceded by _, whereas #invoke functions are not.

main

{{#invoke:Formatnum|main|x|lang=|prec=|sep=}}

mf.formatNum(x, lang, prec, sep)

    if lang ~= nil and mw.language.isKnownLanguageTag(lang) == true then
        -- Convert number to localized digits, decimal separator, and group separators
        local language = mw.getLanguage(lang)
        if compact then
            number = language:formatNum(tonumber(number), { noCommafy = 'y' }) -- caveat: can load localized resources for up to 20 languages
        else
            number = language:formatNum(tonumber(number)) -- caveat: can load localized resources for up to 20 languages
        end
        -- Postprocessing the precision
        if prec > 0 then
            local zero = language:formatNum(0)
            number = number .. dot .. mw.ustring.rep(zero, prec)
        elseif prec < 0 then
            -- TODO: rounding of last decimal; here only truncate decimals in excess
            number = mw.ustring.sub(number, 1, mw.ustring.len(number) + prec)
        end

        -- Append the localized base-10 exponent without grouping separators (there's no reliable way to detect a localized leading symbol 'E')
        if exponent ~= '' then
            number = number .. 'E' .. language:formatNum(tonumber(exponent),{noCommafy=true})
        end
    else -- not localized, ASCII only
        -- Postprocessing the precision
        if prec > 0 then
            number = number .. dot .. mw.string.rep('0', prec)
        elseif prec < 0 then
            -- TODO: rounding of last decimal; here only truncate decimals in excess
            number = mw.string.sub(number, 1, mw.string.len(number) + prec)
        end

        -- Append the base-10 exponent
        if exponent ~= '' then
            number = number .. 'E' .. exponent
        end
    end

    -- Special cases for substitution of ASCII digits (missing support in Lua core libraries for some languages)
    if digit[lang] then
        for i, v in ipairs(digit[lang]) do
            number = mw.ustring.gsub(number, tostring(i - 1), v)
        end
    end

    return number

Use from other Lua modules

main

See also