Lone Wolf Development Forums - String function: counting substring

Ok, I did find I way to do it intrinsically, but it seemed to run slow as well as not be able to handle the cases where we were searching for a string made up of repeated characters very well. So... I went with a workaround requires the input of the number of things that make up the list instead of figuring it out from the string itself since these strings will be generated with things like tagname[], or foreach loops.

Here is what I have for parsing the list

Code:

~ this procedure is used to generate a formatted list with and/or at the end 

~ from an inputted delimited string



~ 

~ Variables

~

~ v_string is our input string which is changed by this procedure

~ v_delim is out list delimiter, unless specified we assume ", "

~ v_andor is the final conjuction used, we assume "and" if not specified

~ v_number is the number of things in our list

~



var v_string as string

var v_delim as string

var v_number as number

var v_andor as string



~ 

~ Internal variables

~

~ x_len - length of v_string

~ x_lastpos - last position of delimiter

~ x_frontend - after we split the string, this is the front piece

~ x_backend - after we split the string, this is the back piece

~



var x_len as number

var x_lastpos as number

var x_frontend as string

var x_backend as string



~ if we do not have a string, get out

doneif (empty(v_string) <> 0)

~ also if v_number is less than 2, get out

doneif (v_number < 2)



~ set defaults

if (empty(v_delim) <> 0) then

   v_delim = ", "

  endif

if (empty(v_andor) <> 0) then

   v_andor = "and"

   endif



~ set length and position variables

x_len = length(v_string)

x_lastpos = lastpos(v_string,v_delim)



~ split our string

x_frontend = left(v_string,x_lastpos)

x_backend = right(v_string,x_len - x_lastpos - length(v_delim))



if (v_number = 2) then

  v_string = x_frontend & " " & v_andor & " " & x_backend

elseif (v_number > 2) then

  v_string = x_frontend & ", " & v_andor & " " & x_backend

  endif

If you are interested here is what I had for my initial attempt at finding and counting substrings. Again, it runs slow and has some issues with more complex search cases.

Code:

~ this procedure counts now many times a given substring appears in a given string



~

~ VARIABLES

~

~ v_string is our string we are searching through

~ v_search is our substring

~ v_count is how many times v_search appears in v_string

~ 



var v_string as string

var v_search as string

var v_count as number



~ if we don't have either, get out

doneif (empty(v_string) <> 0)

doneif (empty(v_search) <> 0)



~

~ ALGORITHM

~

~ String S is of length n

~ Search string s is of length m

~ current search string C(i) is a piece of S starting at position i of length m 

~ we search left to right taking C piecewise. 

~ if we match we increment the count, if not take next search string which is C(i+m+1)

~  this means that last possible position we could have for i is n-m. If we do not 

~ match we shift by 1



var x_n as number

var x_m as number

var x_C as string

var x_endPos as number

var x_ii as number



x_n = length(v_string)

x_m = length(v_search)

~ out search string cannot be greater than our starting string

doneif (x_m > x_n)



x_endPos = x_n - x_m



while (x_ii <= x_endPos)

  x_C = mid(v_string,x_ii,x_m)



debug "pos: " & x_ii & " - " & x_C



  if (compare(x_C,v_search) = 0) then

    v_count += 1

    x_ii += x_m

  else

    x_ii += 1

    endif

  

  loop