Day 18: Use a comma after every item in a series (except the last item).

Commas in a series help the reader to separate items and groups of items in a series. When you have several items in a series, each one should be followed by a comma, except for the last item. Consider this sentence:

“I enjoy eating peaches, plums, pickles, and prunes.”

This series has 4 separate items. Each one is followed by a comma, except “prunes,” which, in this case, is followed by a period.

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Some people will leave out the comma before the “and,” but this can cause confusion when parts of a series have more than one item. Consider this sentence:

“I enjoy eating peaches, plums, pickles and peanut butter and prunes.”

Without that comma before “and,” the reader will not know that I eat my pickles with peanut butter. The comma before “and” is essential to let the reader know how the items are grouped.

By the way: I don't actually recommend eating pickles with peanut butter. Plantains and peanut butter, on the other hand, make a very nice combination.