I have a question about using dashes in a sentence. Can I use them in the following manner? When the young man returned home in the evening, the butler informed him that the other members of the Thompson family -- Jack, John and little Jamie -- had all left the house in the morning. Also, what's the correct formatting to use? Do I hit the hyphen button twice or use the "insert" tool to insert the longer dashes?
I think that's okay, though I confuse myself if there should be two dashes or not, so like "...the Thompson family—Jack, John and little Jamie had all left the house in the morning." It's better to use the actual em dash rather than two hyphens. Sometimes they can appear to be merged, but not always. Or like me, I usually google "em dash", or put a "—" in my sticky notes, copy and paste Oh, and there shouldn't be spaces before and after the dash
When the young man returned home in the evening the butler informed him that the other members of the Thompson family, Jack, John, and little Jamie, had all left the house in the morning.
I just looked this up, because I disagreed with albeldayuia, and feel like Xian Piete was correct, but don't actually know any rules about it off the top of my head. Though I do know how to make em dash's in Microsoft Word (you write, make the dash with a space on either side, and then start and finish another word). Apparently, the correct way to use the two dash's "-" (en dash) and "—" (em dash) does differ, but not significantly. En dash's, "-", are primarily used either to replace the word "to", or to turn a term into a word. For example, "10:30am to 10:45am" turns into "10:30-10:45am", "pages 20 to 45" changes into "pages 20-45", while it's also commonly used to turn "text to speech" or "speech to text" into the singular terms text-to-speech and speech-to-text. Em dash's, which was what you were actually talking about, are used for one of two reasons, to replace other punctuation without awkwardness or to censor words. Censoring is the easier one to explain, and is simply done the same way we use the asterisk to censor, causing "F***" and "F———" to being the same thing, though, as you can see, the second one's actually harder to read and guess at what's being said, even if I used the same number of characters. It's even used to outright censor some words or phrases, such as keeping certain names out of publically released documentation, but keeping all the important information around the name in question intact, to give some discretion. The other use for em dash's "—", to replace awkward punctuation, is a lot more difficult to detail without basically giving examples and hope it's understood. One example is that it can be used to prevent the overuse of comma's or brackets in order to prevent confusion. I'm going to be using the example given the site I looked at because it's actually applicable in a story writing context, but I'm adding my own "worst version" to give a greater showcase for why the em dash is used. Mine is the first, and the second and third are taken from the site. After a split second of hesitation, the second baseman leaped for the ball, or, rather, limped for it. After a split second of hesitation, the second baseman leaped for the ball (or, rather, limped for it). After a split second of hesitation, the second baseman leaped for the ball—or, rather, limped for it. The difference between the three is clear, despite using the same words. The first (that I adjusted) has three words with comma's after them in a row, and just seems awkward to read. The second not only ends the sentence with brackets, but also uses them for a directly continued aside that adds to the sentence instead of simply being related to it. The third, with the em dash, easily showcases that it's a continuation of the sentence, but gives enough of a break to showcase that there's a small disconnect between the desired action and actual action that could be taken in the situation. Admittedly, there's also the option of rewording the sentence so that the normal punctuation for doing this, comma's, is less awkward to use, but that can still be more awkward than using an em dash (the following is purely my variants, and you decide which one's the least awkward): After a split second of hesitation, the second baseman leaped for the ball, well, limped for it. After a split second of hesitation, the second baseman leaped for the ball — well, limped for it. Link to the site where I went to for clarification: https://www.grammarly.com/blog/dash/
The function of the dash used in OP's sentence is different from the one in your example. It's replacing a colon, not a comma. Using a comma would alter the meaning. It'd seems as if "the other members of the Thompson family" is another list item in the same level as "Jack, John, and little Jamie" while actually it's the label of the list and the dash is used to replace a colon that's meant to introduce the list
Except it isn't replacing a colon, at most it's replacing a semicolon, but even then a semicolon's changing the subject. Colon's in grammar are a dividing line, after one you cannot go back to the sentence you were writing, just like with a full stop. The purpose of a colon is akin to an equal's sign in maths: saying that this is the solution or answer to what had been previously said in the sentence. Similarly to how in math's the equation "answer 27+(4+6=10)*15" doesn't need, or make sense with, the equal's sign, putting a colon into a sentence that continues after giving a small descriptor doesn't make sense. Here's some links that would help you with this. I fully admit that I didn't actually peruse the colon link and answered entirely based on my own opinion, but that doesn't change the fact that the original sentence doesn't continue after using a colon. https://www.grammarly.com/blog/colon-2/ https://www.grammarly.com/blog/semicolon/ https://www.grammarly.com/blog/comma/
Ooh that's true, I didn't know the sentence must stop after a list introduced by a colon. But to put semicolon there is a common misuse of it. Semicolon divides items in a list, not to precede a list. To use a comma is still incorrect either. The best option is to place the list between dashes