Hi how to create a regular expression which the pattern should only have 1 instance of "
For example:
1. STRING"
2. "STRING
3. STRI"NG
4. STRING""
5. "STRING"
Result:
1. STRING""
2. ""STRING
3. STRI""NG
4. STRING"" (No change since 2 instance of ")
5. "STRING" (No change since 2 instance of ")
Something like this:
with t as (
select 'STRING"' as s from dual union all
select '"STRING' from dual union all
select 'STRI"NG' from dual union all
select 'STRING""' from dual union all
select '"STRING"' from dual union all
select 'STRING' from dual union all
select '"STR"ING"' from dual union all
select '"' from dual union all
select '""' from dual union all
select '"""' from dual
)
select
s,
regexp_replace(s,'^([^"]*)"([^"]*)$', '\1""\2') new_s
from t
Output:
+-----------+-----------+
| S | NEW_S |
+-----------+-----------+
| STRING" | STRING"" |
| "STRING | ""STRING |
| STRI"NG | STRI""NG |
| STRING"" | STRING"" |
| "STRING" | "STRING" |
| STRING | STRING |
| "STR"ING" | "STR"ING" |
| " | "" |
| "" | "" |
| """ | """ |
+-----------+-----------+
Explanation:
^ # asserts position at start of a line
( # 1st capturing group
[^"]* # matches characters that are not the character ", zero or more times
)
" # matches the character " literally
( # 2nd capturing group
[^"]*
)
$ # asserts position at the end of a line
Check it online with rextester.
