Worked beautifully

If you would like to do preview, you can use Really Simple CSV Importer Debugger add-on. See Other Notes tab. Thanks!

Oh, good to know! Sorry I missed that earlier, thanks.

(How about incorporating the debugger directly into the plugin? It could be as simple as having a checkbox next to the import button that says “Enable debug mode?”)

Well, to use debugger add-on, please download the add-on plugin from gist, upload php file to your wp plugin directory, and activate it. During it activated, the importer will be debug & dry run mode. Every importing will no longer insert data to your database. If you finish checking your data and you would like to import csv data to database, simply deactivate debugger add-on, then re-import the csv. Do you know what I mean? Probably my english is bad ??

That makes sense, and your English is excellent. ?? But it would be far easier if it was integrated into the plugin, so you could easily debug, and then import.

An even better workflow would be to upload the file, show the data (to let the user check it), and then have a “confirm” button to run the import. 1-2-3-done! ??

(But even if you don’t do that, the plugin worked really well for me and saved a TON of time! Thanks again!)

Ah, I’ve got the point. My plugin extends built-in WP_Importer class because extending core class is always good way to hack, but unfortunately, this class have not the feature of previewing. So I made filter hook and another debugger add-on. However, I will keep considering to add preview feature, and thanks again for your nice review!