Replace multiple spaces

Question

Hi dear experts,
I need a function/procedure that replaces multiple spaces by one space.
(This is because of an Application Express representation of strings in a report).
(I have to replace ' ' by '_' in this post just because of the same phenomenon).
Strings like "This___is_an_________example"
should become " This_is_an__example".
I need something like:
create or replace function remove_multispaces(text_in in varchar2) return varchar2 is
begin
while instr(text_in,'__') >0 /* two blanks */
loop
execute immediate replace (text_in,'__','_'); /*replace 2 blanks by 1 */
end loop;
return (text_in);
end remove_multispaces;
But this is definitely not working.
Thank you for your help,
Hergen.

Answer 1

SQL> ed
Wrote file afiedt.buf
1 create or replace function replace_multispaces(in_str varchar2) return varchar2 is
2 out_str varchar2(100):=in_str;
3 begin
4 while(instr(out_str,'__')>0) loop
5 out_str:=replace(out_str,'__','_');
6 end loop;
7 return(out_str);
8 exception
9 when others then
10 dbms_output.put_line(sqlerrm);
11* end;
SQL> /
Function created.
SQL> select replace_multispaces('This___is_an_________example') from dual
2 ;
REPLACE_MULTISPACES('THIS___IS_AN_________EXAMPLE')
This_is_an_example
SQL>