Do you put a comma before and?

Answer 1

It depends on the structure of the sentence. 1. If it is a compound sentence with one subject, the answer is usually no. Example: Bob ate his dinner and went to bed. 2. If it is a compound sentence with two subjects and two verbs (or more), the answer is yes. Example: Bob ate his dinner, and Suzie went to bed. The key is, could each half of the sentence stand as a separate sentence? If so, use a comma. 3. In lists, the comma before "and" is optional. The important thing is to be consistent. Examples: For dinner, I had steak, potatoes, iced tea, and chocolate cake. For dinner, I had steak, potatoes, iced tea and chocolate cake. Both are correct. Some people advocate using the last comma (called the terminal comma) to clarify the meaning. For instance, the two following sentences are both correct, but the second one doesn't have the terminal comma, and the meaning is ambiguous because of it: I dedicate this book to my parents, Ayn Rand, and God. I dedicate this book to my parents, Ayn Rand and God.

Answer 2

If I understand what you're asking, this is called the "Oxford Comma", and whether to use it or not is a matter of style. You should consult the style guide for whatever you're writing for.

Some style guides say that "apples, Oranges, and lemons" is preferred, and others say that it should be "apples, oranges and lemons" instead.

I personally prefer the Oxford comma, but some people really seem to hate it for some reason.