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On 01/21/2015 09:37 PM, Matthew Wild wrote:

On 21 January 2015 at 10:29, Rena <hyperhacker@gmail.com> wrote:

On Wed, Jan 21, 2015 at 2:33 AM, DouOlivia <olivia2046@hotmail.com> wrote:

Hi there,

Should have performed a search in the list first, but I’m afraid I cannot
come out with a good query. Here’s the question: Is there a library that can
calculate the ratio of numberic or alphanumeric words in a given string (the
actual scenario is to use a document’s content so the string will be very
long)? E.g  for string “34 aaa A-7SXD bbb ccc”, the ratio is calculated as
0.4.

Seems like a simple task for Lua's pattern matching:

function countMatches(str, pat)
     local c = 0
     for word in str:gmatch(pat) do c = c + 1 end
     return c
end

Couldn't resist... this version of countMatches() is shorter and
faster (on my machine at least) in long documents:

function countMatches(str, pat)
     return select(2, str:gsub(pat, "%0"))
end

function ratio(text)
         return countMatches(text, '%d+') / countMatches(text, '[%a%p]+')
end
I don't think that's the result the OP was looking for. What if the test string is, 
"34 aaa A-7S8X9D bbb ccc"
Both of your implementations are returning 0.57 but I think that the OP still wanted 0.4 although he didn't really define it very precisely (e.g. how does the string "% 4" evaluate?). 

Maybe something like:

local function ratio( str )
    local tot, num = 0, 0;
    local sfind = string.find;
    for word in str:gmatch("%S+") do
        tot=tot+1;
        if sfind(word,"%d") then num=num+1; end
        end
    return num / tot;
    end;

You could do a similar approach with gsub() also.