Commas 2
Complex lists
Complex lists:
Commas are also used to separate more complex 'list-like' items in a sentence.
Tom decided to take his backpack, enough clothes for 10 days, a copy of his passport, and a map
The government immediately declared a civil emergency, limited civilian access to the area, and ensured the immediate safety of the inhabitants.
Commas and their influence on meaning
The problem with commas and and:
Note that in complex lists it is sometimes necessary to place a comma before an and separating the last items if you want them to be treated as a separate idea or event. (This would seem to contradict what was said in Commas Lesson 1, but, sometimes the last two items need to be grouped together (no comma) and sometimes they need to be kept deliberately apart (so insert a comma). The video that goes with this lesson explains this a little, and we have extended this with our examples and explanation below.
Tom decided to take his backpack, enough clothes for 10 days, a copy of his passport, and a map.
Grammar nerds do not always agree about the rule, but your grammar choices are not about following rules!
Your choices are about understanding how texts are constructed to create meaning, and choosing structures that produce a text that is clear and unambiguous. Look at the difference in meaning between the following examples (adapted from Grammar-Monster.com) that occurs because of one little comma.
Jack left the pub with John (a policeman) and Simon.
Jack left the pub with John, (a policeman), and Simon.
Control over how you group your information
Controlling information with commas:
You do not always have to separate items in a list with a comma. Sometimes you purposely do not do so in order to keep blocks of text together when it makes up one idea. Notice how the comma placement changes each of the meanings below slightly:
Communication can also be non-verbal, with dancing, action, songs, and poetry.
Communication can also be non-verbal, with dancing action, songs, and poetry.
Communication can also be non-verbal, with dancing action songs, and poetry.
Communication can also be non-verbal, with dancing action songs and poetry.
The point here is that you control how the information in your text is grouped by the choices you make with your commas.