Replace new lines with a comma delimiter with Notepad++?

Here's what worked for me with a similar list of strings in Notepad++ without any macros or anything else:

  1. Click Edit -> Blank Operations -> EOL to space [All the items should now be in a single line separated by a 'space']

  2. Select any 'space' and do a Replace All (by ',')


Open the find and replace dialog (press CTRL+H).

Then select Regular expression in the 'Search Mode' section at the bottom.

In the Find what field enter this: [\r\n]+

In the Replace with:

There is a space after the comma.

This will also replace lines like

Apples

Apricots
Pear

Avocados
Bananas

Where there are empty lines.

If your lines have trailing blank spaces you should remove those first. The simplest way to achieve this is

EDIT -> Blank Operations -> Trim Trailing Space

OR

TextFX -> TextFX Edit -> Trim trailing spaces

Be sure to set the Search Mode to "Regular expression".