I learned it from the guide by Santi Younger (via @Louiscard). It’s really useful. I make an adjustment to the Obsidian_to_Anki plugin setting. The original one is:
((?:[^\n][\n]?)+) #flashcard ?\n*((?:\n(?:^.{1,3}$|^.{4}(?<!<!--).*))+)
When I type “#" in the document, there will automatically appear “#flashcard". If I tap enter, “#flashcard” will be typed but also followed by a space. I need to delete the space to fit the plugin setting. I add an extra space after “#flashcard" in the setting, so I just need to tap enter and don’t need to delete a space. The new setting is changed to:
((?:[^\n][\n]?)+) #flashcard ?\n*((?:\n(?:^.{1,3}$|^.{4}(?<!<!--).*))+)
This works. It’s more convenient.