Regular Expression - Not matching certain characters and position of characters - regex

Question

SOLUTION:
Finally solved it using the regex provided by Gary_W below and a simple PowerShell command that uses the discussed replacement function. So there was no need to use the built in regex activity in the software we use. Here´s the PS:
"100,000.00" -replace "([,.]\d{2}$)|[,.]",""
Regular Expressions are freaking me out. I cannot get used to that logic. However, I think my current RE problem is a quite simple one bur I cannot make it work :(
So here´s what I want to achieve:
I want the RE to match only the digits before the last two decimal places.
Thus, the RE must ignore any "." and "," AND always the last two digits.
> Examples:
> 1.000.000,00 --> 1000000
> 123,456.00 --> 123456
> 100.000,00 --> 100000
> 10.000,00 --> 10000
> 10,000.00 --> 10000
> 1.000,00 --> 1000
> 100,00 --> 100
> 99.88 --> 99
> 99,88 --> 99
> 1,23 --> 1
> ...
Any ideas how to get this working?

Answer 1

Here's how I would do it in Oracle, for what it's worth. Maybe the regex used here will give you an idea. Read the regex as "Look for a match of a comma or a decimal followed by 2 digits at the end of the line, OR a comma or a decimal and replace with nothing.
Note the match for the optional decimal places at the end needs to be first in the regex, otherwise the single characters are matched first, making the 2 decimal places non-existent and thus not matched.
SQL> with tbl(str) as (
select '1.000.000,00' from dual union all
select '123,456.00' from dual union all
select '100.000,00' from dual union all
select '10.000,00' from dual union all
select '10,000.00' from dual union all
select '1.000,00' from dual union all
select '100,00' from dual union all
select '99.88' from dual union all
select '99,88' from dual union all
select '1,23' from dual union all
select '3' from dual
)
select str,
regexp_replace(str, '([,.]\d{2}$)|[,.]') fixed
from tbl;
STR FIXED
------------ ------------
1.000.000,00 1000000
123,456.00 123456
100.000,00 100000
10.000,00 10000
10,000.00 10000
1.000,00 1000
100,00 100
99.88 99
99,88 99
1,23 1
3 3
11 rows selected.
SQL>
Just saw the regexr link, plugging in my regex looks like it works with the global flag. The characters you wish to remove are highlighted.

Answer 2

In which language/with which tool? With sed, you can do:
sed 's/\(.*\)[\.,]../\1/;s/[\.,]//g'
In perl it's similar, just without the initial backslashes:
perl -pe 's/(.*)[\.,]../\1/;s/[\.,]//g'
This is done with two regexes, by the way. The first one reads "save all that you can, up to a dot or a comma followed by two chars, and then replace the whole match with that". The second one reads "replace all dots and commas with nothing", that is, "remove all dots and commas".
In regexr.com you can use "Replace" in Tools to replace the match with the first capture group. Just put (.*)[\.,].. in Expression, and $1 in Replace, to see the first regex working. Then you can do something similar with the second one, as regexr doesn't support chaining of expressions, as far as I can see.