i.e. and e.g. are not interchangeable!

Pet peeve of mine.

• “i.e.” stands for Latin “id est”, meaning “that is.”
• “e.g.” stands for “exempli gratia”, meaning “for example.”

If you have trouble remembering which is which, think of “for egsample.”

And for both of them, you add periods after each letter and a comma at the end. The comma is there because it’s the same as saying “for example,” or “that is,”:

• I’m working on a side project, i.e., building an app that detects the presence of hot dogs.
• I like eating hot dogs, e.g., chili dogs, corn dogs, Chicago-style dogs, NY style dogs, etc.