・You want to use commas as delimiters to output in CSV format. ・You do not want a newline so that you can display processing progress on a single line. The two optional arguments for the print() ...

I wrote code to check the line break code of data received serially from an Arduino. Using the repr() function displays the string including line break characters, like '688,2.22\r\n' ⇒ It was ...