Parsing a string in PL/SQL?

Question

I am parsing a string in PL/SQL and at a certain point(Length 45) of the string I would like to add a carriage return (Chr(10)), then continue with the string at that point and then again if the string is greater than Length 45 add a carriage return.
I program in Powerbuilder and have figured it out, but I have a problem when trying to add a carriage return at a certain point in the string in PL/SQL. There is the REPLACE(), but that will replace everything, but I only want to add it at that certain point of the string. With the PB function I can add the carriage return at a certain point, see code:
Li_pos = PosA( Ps_data, '*')
DO WHILE Li_pos > 0
ll_length = Li_pos - ll_old_pos
IF ll_length > 45 THEN
ll_old_pos = Li_pos
Ps_data = ReplaceA( Ps_data, Li_Pos, 1, ls_carriage_rtn) **This function gives me the ability to add a carriage return at a certain point in the string. **
Li_pos = PosA( Ps_data, '*', Li_pos + 1 + ls_carriage_rtn)
ELSE
Li_pos = PosA( Ps_data, '*', Li_pos + 1)
END IF
LOOP
I have incorporated the same logic in PL/SQL but I am looking for something similar to the ReplaceA function in PB, that will replace at a certain point in a string. I use an '*' as a placeholder and measure the length. Below is the PL/SQL code:
t_pos NUMBER;
t_old_pos NUMBER;
t_length NUMBER;
BEGIN
t_old_pos := 0;
t_pos := INSTR(in_model_list, '*');
WHILE t_pos > 0 LOOP
t_length := t_pos - t_old_pos; -- This looks at current position minus the old position, measures the length
IF t_length > 45 THEN
t_old_pos := t_pos;
*** add that carriage return
t_pos := INSTR(in_model_list, '*', t_pos + 1 + Chr(10)); -- get the new position
NULL;
ELSE
t_pos := INSTR(in_model_list, '*', t_pos + 1);
END IF;
NULL;
END LOOP;
Here is the data, what it looks like: William 112,* 500-A,* 500-U,* 520,* 560-A,* 560-E,* 680-E,* 680-F,* 680-V*
Any help would be much appreciated.
Thank you,
William
Edited by: William on Feb 28, 2012 6:56 AM

Answer 1

Frank Kulash wrote:
[example]I played with your example and came to this:SQL> WITH my_string AS
  2         (SELECT '1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890'
  3                   AS mt
  4            FROM DUAL)
  5     ,  line_length AS
  6         (SELECT 13 AS chars
  7            FROM DUAL)
  8      SELECT LISTAGG (REGEXP_SUBSTR (mt,'(.{'|| line_length.chars|| '})', 1, LEVEL),chr(10)) WITHIN GROUP (ORDER BY LEVEL)
  9             ||chr(10)
10             ||substr(mt,-mod(LENGTH (mt),line_length.chars)) as wrapped_text
11        FROM my_string
12        CROSS JOIN line_length
13  CONNECT BY LEVEL < 1+LENGTH (mt) ;
WRAPPED_TEXT
1234567890123
4567890123456
7890123456789
0123456789012
3456789012345
6789012345678
9012345678901
2345678901234
5678901234567
8901234567890
1234567890123
WRAPPED_TEXT
4567890123456
7890
SQL>*[Edit]* annotated that this is 11g only...
Edited by: T.PD on 29.02.2012 21:17