Do you know how to use the Oxford comma?
Updated by Matthew Parker [SSW] 11 months ago. See history
The "Oxford comma" (so-called because the Oxford University Press style guidelines require it) has the distinction of being one of the most hotly debated elements of the English language.
Figure: Some people love Oxford commas, some hate them
Knowing when to use the Oxford comma helps to create more consistent and easier to read documentation.
Also referred to as a series comma or serial comma, an Oxford comma is placed in a series of three or more items before the conjunction. It can be used in both "and" and "or" lists as the last comma separating a series of items. It works to help order these items and provide a distinction between the items on the list, particularly the last two items. An Oxford comma is often unnecessary, though.
Figure: A sentence with quite different meaning depending on whether an Oxford comma is used or not
The rule is that a comma should only be used between the last two items of a list if it removes potential ambiguity, otherwise no comma is required
Let's look at some examples to illustrate the rule in action.
Adam, Matt, and Lee got on a call to discuss the use of the Oxford comma
❌ Figure: Bad example - the extra comma after "Matt" is unnecessary and just adds clutter
The ice cream comes in an assortment of flavours including banana and strawberry, strawberry and mango, and blueberry.
✅ Figure: Good example - without the Oxford comma, it's not clear whether the flavour is strawberry and mango or mango and blueberry
This short TED Ed talk covers the topic well.