PL/SQL - Split string into an associative array - oracle

Question

In plsql is there a way to split a string into an associative array?
Sample string: 'test1:First string, test2: Second string, test3: Third string'
INTO
TYPE as_array IS TABLE OF VARCHAR2(50) INDEX BY VARCHAR2(50);
a_array as_array;
dbms_output.put_line(a_array('test1')); // Output 'First string'
dbms_output.put_line(a_array('test2')); // Output 'Second string'
dbms_output.put_line(a_array('test3')); // Output 'Third string'
The format of the string does not matter for my purposes. It could be 'test1-First string; test2-Second string; test3-Third string'. I could do this with a very large function manually splitting by commas first and then splitting each of those but I'm wondering if there is something built in to the language.
Like I said, I am not looking to do it through a large function (especially using substr and making it look messy). I am looking for something that does my task simpler.

Answer 1

There is no built in function for such a requirement.
But you can easily build a query like below to parse these strings:
SELECT y.*
FROM (
select trim(regexp_substr(str,'[^,]+', 1, level)) as str1
from (
SELECT 'test1:First string, test2: Second string, test3: Third string' as Str
FROM dual
)
connect by regexp_substr(str, '[^,]+', 1, level) is not null
) x
CROSS APPLY(
select trim(regexp_substr(str1,'[^:]+', 1, 1)) as key,
trim(regexp_substr(str1,'[^:]+', 1, 2)) as value
from dual
) y
KEY VALUE
------ --------------
test1 First string
test2 Second string
test3 Third string
Then you may use this query in your function and pass it's result to the array.
I leave this exercise for you, I believe you can manage it (tip: use Oracle's bulk collect feature)

Answer 2

This method handles NULL list elements if you need to still show that element 2 is NULL for example. Note the second element is NULL:
-- Original data with multiple delimiters and a NULL element for testing.
with orig_data(str) as (
select 'test1:First string,, test3: Third string' from dual
),
--Split on first delimiter (comma)
Parsed_data(rec) as (
select regexp_substr(str, '(.*?)(,|$)', 1, LEVEL, NULL, 1)
from orig_data
where str is not null
CONNECT BY LEVEL <= REGEXP_COUNT(str, ',') + 1
)
-- For testing-shows records based on 1st level delimiter
--select rec from parsed_data;
-- Split the record into columns
select trim(regexp_replace(rec, '^(.*):.*', '\1')) key,
trim(regexp_replace(rec, '^.*:(.*)', '\1')) value
from Parsed_data;
Watch out for the regex form of [^,]+ for parsing delimited strings, it fails on NULL elements. More Information