Notepadd++ Python Script: Delete everything between the last 3 " - " if line starts with X

Question

Looking at the end of the line counting the " - " backwards (notice the spaces) and delete the text but only if the line starts with fx TEST.

Before

TESTMouse - Dog - CAT - Fish
Mouse - Dog - CAT - Fish
TESTRat - Whale - Bird - Horse - Snake

After

TESTMouse
Mouse - Dog - CAT - Fish
TESTRat - Whale

This is beyond my ability to write myself and I have not found anything that would work in my searches.

Answer 1

No needs for Notepad++ PythonScript, a simple find and replace is enough:

• Ctrl+H
• Find what: ^TEST.*?\K(?: - \w+){3}$
• Replace with: LEAVE EMPTY
• TICK Match case
• TICK Wrap around
• SELECT Regular expression
• UNTICK . matches newline
• Replace all

Explanation:

^           # beginning of line
    TEST        # literally
    .*?         # 0 or more any character, not greedy
    \K          # forget all we have seen until this position
    (?:         # non capture group
        - \w+      # space, hyphen, space, 1 or more word character
    ){3}        # end group, must appear 3 times
$           # end of line

Replacement:

Screenshot (before):

Screenshot (after):