Using the dash
You’ll sometimes come across a piece of writing that looks like the literary equivalent of machine-gun fire—a series of thoughts – disconnected ideas – rambling conjectures and assertions—that the writer has plopped down on the page – almost randomly – perhaps to give the impression of urgency and immediacy – but in fact only giving the impression of a disordered mind—now where was I?
This technique always results in readers forgetting the beginning of the sentence before they’ve reached the end. Which is not what you want.
Use dashes sparingly; instead, consider an alternative construction for the sentence, perhaps involving a semicolon.
Still, there is a place for dashes, and you can employ them successfully by remembering a few simple guidelines. First, there are 2 kinds of dashes:
the em dash (—), which is mainly used to separate
the en dash (–), which is mainly used to join.
The em dash (use ctrl + alt + minus on the numeric keypad for PC; use shift + option + hyphen on the numeric keypad for Mac) should be used to signify a sudden change in the direction of a sentence (e.g. ‘It’s a big building with patients—but that’s not important right now.’). It can also be used to add emphasis in a parenthetical expression (e.g. ‘Gaius Julius Caesar Augustus Germanicus—better known as the murderous pervert Caligula—was assassinated in 41 AD.’).
There are other situations where an em dash may be appropriate, such as when a sentence requires more than one parenthetical interpolation (e.g. ‘The Stasi were persuasive fellows and they wanted to know everything about me—everything my passport could already have told them (name, rank and serial number)—so they could then forget it and start all over again.’). This way you don’t wind up with lots of brackets within brackets, which is confusing to the reader.
The en dash (use ctrl + minus on the numeric keypad for PC; use option + hyphen on the numeric keypad for Mac) is much more versatile and useful. Use it to show spans of figures (pages 45–67), time (May–December), or distance (Melbourne–Launceston ferry).
Don’t use it as a substitute for ‘from’ (write ‘his killing spree lasted from 1986 to 2008’ NOT ‘his killing spree lasted from 1986–2008’). And don’t substitute an en dash for ‘between’ (write ‘his victims were aged between 23 and 67’ NOT ‘his victims were aged between 23–67’).
See also:
