Hyphens and Dashes look similar.
This is a hyphen: –
This is a dash: — (made by writing two hyphens)
You can combine two words with a hyphen to create a compound adjective or name:
I love Chinese–American food.
Mary–Lou Conway–Richardson had the longest name in her class.
Numbers from 21 to 99 are also written with a hyphen:
My great–aunt Eileen is almost ninety–eight.
It’s Brad’s twenty–first birthday next week.
Instead of writing “to”, you can use a hyphen.
Malachi took the Boston to New York City train.
Malachi took the Boston–New York City train.
I prefer temperatures in the 20 to 25C range.
I prefer temperatures in the 20–25C range.
Dashes are less formal than colons, semicolons, parentheses, commas and ellipses, but they can be used some of the same ways.
A dash can replace a colon, but only if it is not followed by a list.
Right: There’s only one person that I love in the whole universe: you.
Right: There’s only one person that I love in the whole universe — you.
Right: Lee has three favourite sports: curling, water polo, and lacrosse.
Wrong: Lee has three favourite sports — curling, water polo, and lacrosse.
In informal writing, you can replace a semicolon with a dash, if the two clauses are short and contrasting.
I’m vegetarian; my brother is a butcher.
I’m vegetarian — my brother is a butcher.
Parenthetical (or non-restrictive) phrases can be set off by commas, parentheses, or dashes. These punctuation marks are not interchangeable, however.
In phrases that start with who or which, a commas is best.
Right: Dominic, who came in first place this year, began training at age five.
Okay: Dominic (who came in first place this year) began training at age five.
Bad: Dominic — who came in first place this year — began training at age five.
When the parenthetical phrase is an independent clause, you can’t use commas
Right: I was devastated about dropping all my china (my grandmother had given this heirloom set to me at my wedding), but I managed to salvage some of it.
Right: I was devastated about dropping all my china — my grandmother had given this heirloom set to me at my wedding — but I managed to salvage some of it.
Wrong: I was devastated about dropping all my china, my grandmother had given this heirloom set to me at my wedding, but I managed to salvage some of it.
Use ellipses or a dash depending whether you want to create a slow trailing off or a quick break.
Slow: I wonder where I put my keys…. Oh! I know!
Fast: I wonder where I put my keys — Oh! I know
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