Regular Expression - difficulties with comma - regex

Question

I am facing two problems with comma:
I want to search for DE 99, SF 99 and DE 99 SF 99 in the same pattern. Kindly note that the only difference is the comma. I have an input with Data Element number (DE) and its Subfield number (SF). SF isn't always present, but I managed to deal with in the code below. The issue is that some times DE and SF comes separated by "," other times not.
The other problem is, that the currency value or any value with "," is missed after the comma. I placed below what I am doing and some test case examples. Kindly note that the value can be number or alphanumeric.
Found and read correctly the value
wholeLine: DE 3, SF 1 = 20
OUTPUT: DE 3, SF 1 = 20
Found and read correctly the value
wholeLine: DE 26 = 6538
OUTPUT: DE 26 = 6538
Found but read wrongly the value because only reads before “,”
wholeLine: DE 4 = 3,727
OUTPUT: DE 4 = 3
Not Found
wholeLine: DE 63 SF 2 = xyz
Pattern patternDE = Pattern.compile("DE \\d+(, SF \\d+)* = \\w+");
Matcher matcherDE = patternDE.matcher(wholeLine);
while (matcherDE.find()){
String wholeThing = matcherDE.group();
System.out.println(wholeThing);
}

Answer 1

Looks like you should be using
DE \\d+,?( SF \\d+)* = \\w+
? is a quantifier for one or none, so you're looking for DE followed by a space, then one or more digits, then one or zero commas, followed by the rest of your regex that's already working.
The problem you're having with the last part of your output is that you're matchin word characters, which don't include commas. Try matching non-spaces instead \\S

Answer 2

the part (, SF \\d+)* acts as a group and can not tell whether comma , exists or not separately. So by moving the , out of the group, the expression should be ok.
And for the currency problem, try replacing \\w+ with [\w,]+, to include comma.
DE \\d+(, SF \\d+)* = \\w+ // original
DE \\d+,?( SF \\d+)* = \\w+ // exclude comma from group
DE \\d+,?( SF \\d+)* = \[\w,]+// currency separator