The use of a comma before "rather than"

Question

Could you tell me if I need to use a comma before rather than in the following sentences?

This tablet comes in grey(,) rather than in gold.

I prefer to take the bus to work(,) rather than going by car.

I'm cofused because I've seen similar sentences with and without a comma before rather than. I'd like to know the logic behing using a coma and not using it before rather than.

Answer 1

"Rather than" can be a conjunction or a preposition.

In your example, it is being used as a conjunction to join the two parallel colour options together. Logically, you would not then use a comma to separate them:

This tablet comes in grey rather than in gold.

You could also write this sentence using "rather than" as a preposition:

Rather than gold, this tablet comes in grey.

Answer 2

Rather has its many uses. Rather than, a derived phrase acts as either conjunction, or a preposition.

This tablet comes in grey rather than in gold.

As a conjunction, parallel grammatical constructions appear on each side of rather than. When used to coordinate verbs, it indicates that something is done in place of something else, and the verbs are inflected in the same way. It is also used to join nouns, adjectives, adverbs, or prepositions in the sentence

Examples:

• He decided to call rather than text.
• I drink coffee rather than tea.
• He bought red rather than green peppers.
• She eats slowly rather than quickly.

I prefer to take the bus to work rather than going by car.

This sentence has the same explanation as the above one. In both these cases, rather than is acting as conjunction. While used as a conjunction, we do not use a comma to separate the sentences.