Regular expression extracting last element starting with &[?

Question

The regular Expression should be applied to the following string:

[Product].[Product Catalog].[Product].&[50]&[53]&[DE]&[1ST_HQ]&[50_54_36]

As-Is:
The following regular Expression is applied:

(?:&\[).+(?:\])

That Returns:

&[50]&[53]&[DE]&[1ST_HQ]&[50_54_36]

To-Be:
I want to Change that regular expression to return

&[50_54_36]

only. Any Idea?

Answer 1

You could simply use the end of the string $ anchor if you want to extract the last element. Implementing Non-capturing groups for those characters is not necessary, so you can remove the groups as well.

&\[[^]]+]$

Explanation:

&        # '&'
\[       # '['
 [^]]+   #    any character except: ']' (1 or more times)
]        # ']'
$        # before an optional \n, and the end of the string

Live Demo

Alternatively, I would suggest using a capturing group to match and capture the match result. The .* here will eat up all characters up until the last occurrence of &[. You can then refer to group #1 for your match.

.*(&\[[^]]+])

Answer 2

Use this regex:

.*\K&\[.+\]

The .* instructs the regex engine to match all, then backtrack to match, so our match will start from the end of the string backwards and match the last. \K keeps the match afterwards.

See a regex demo!