How to extract last X digits from fixed Y digit number using RegEx?

How to extract last X digits from fixed Y digit number using RegEx?

input : 1234567890123456

• ((?=\d{16}$)\d{10}|) gives 1234567890

But

• ((?=\d{16}$)\d{10}$|) does not give 7890123456

basically, I want last 10 digits if it is compulsory 16 digit no else nothing.

Looks like you're not using Java and cannot use capture groups.

For your tibco tool you can use this regex with validation of 16 digits to grab last 10 digits:

(?<=^\d{6})\d{10}$

RegEx Demo

RegEx Breakup:

• (?<=^\d{6}) is a positive lookbehind to assert that we have 6 digits from start to previous position
• \d{10}$ matched 10 digits at the end of string