DASHES

'' PUNCTUATION''

Using Dashes

Generally speaking, the dash does not have a unique role. It is usually used as an alternative to another type of punctuation.

When used to extend a sentence, a dash can replace a semicolon (;), a colon (:), or three dots (...) used as a pause for effect.

When used as parentheses, dashes are alternatives to brackets or commas. 

There are two kinds of dash: the em dash (—) and the en dash (–). The em dash is the same length as the character "M" (uppercase), and the en dash is same length as the letter "n" (lowercase).

As dashes do not feature on a standard keyboard, lots of people use hyphens instead of dashes. That's not really such a crime, but it's something of a missed opportunity to show off that you know the difference between a hyphen and a dash. Some writers like to use two hyphens (--) to represent one dash to differentiate.

Here are the four main dash-like characters ordered longest to shortest: 

Name	Punctuation	How To Get One
em dash	—	Ctl + Alt + minus (on the numeric pad)
minus sign	−	minus (on the numeric pad)
hyphen	-	- (the key to the right of "0")
en dash	–	Ctl + minus (on the numeric pad)

Here they are again but in a bigger font size.

Name	Punctuation
em dash	—
minus sign	−
hyphen	-
en dash	–

The hyphen and the en dash are almost indistinguishable from each other when using normal size fonts.

Using Dashes with Times and Dates

A dash can be used between times and dates. (A dash will usually replace the words from…to or between…and.) For example:

• USSR existed 1922-1991.

Note: This is an alternative to:
• USSR existed between 1922 and 1991.
• USSR existed from 1922 to 1991.
• USSR existed 1922 to 1991.
• The project will be delivered January-June.
• I will visit 13 January-24 January
• I will visit 0800-0900.

The format with the dash is most common in tables. For example:

Time	Event
0800-0830	Introduction
0830-0930	Lesson 1
0930-1030	Lesson 2

Note: If you're a stickler for the rules, use an en dash between times and dates. You will get away with a hyphen. Do not use an em dash.

Using Dashes in Compound Adjectives with Equal Parts

A dash can replace a hyphen in a compound adjective with two equal elements. For example:

• The India-Pakistan issue
• The NATO-Warsaw Pact agreement

Note: If you're a stickler for the rules, use an en dash in your adjective. You will get away with a hyphen. Do not use an em dash.

Using Dashes to Extend Sentences

A dash can be used to replace a colon which is offering more information about something mentioned previously in the sentence. For example:

• She demanded just one thing from her students: effort. 
• She demanded just one thing from her students — effort. 

A dash can be used to replace a semicolon which replaced a full stop / period to give a smoother transition between two sentences: For example:

• She demanded effort from her students. That's all she ever asked for. 
• She demanded effort from her students; that's all she ever asked for. 
(semicolon used to give a smoother transition between the sentences)
• She demanded effort from her students — that's all she ever asked for. 
(semicolon replaced by a dash)

A dash can be used to replace three dots used as a pause for effect. For example:

• As she prodded through the sludge, something caught her eye. It was the unblemished unmistakable sparkle of… the diamond on her grandmother's ring. 
• As she prodded through the sludge, something caught her eye. It was the unblemished unmistakable sparkle of — the diamond on her grandmother's ring. 

Good news! There are specific rules about when to use a semicolon, a colon, or three dots, so you have to know what you're doing if you choose one of them. One of the good things about a dash is that it can be used as a substitute for all three.

Bad news! Using dashes every single time is not a good look. It will also cut down on your options for expressing yourself and showcasing your grammar skills. Therefore, you must still learn how to use the others. (You could think of the dash as a get-out-of-jail-free card that you can use occasionally.)

Note: If you're a stickler for the rules, use an em dash to extend a sentence. You will get away with an en dash or a hyphen.

Read more about dashes to extend a sentence

Using Dashes as Parentheses

We're all familiar with putting explanations or afterthoughts in brackets (just like this). But, brackets are just one of the choices you have for inserting extra information into a sentence. You can also use commas or dashes. For example:

• Mark Jones (who has lived in our village for 20 years) is the world Scrabble champion and the national Cluedo champion. 
(brackets used)
• Mark Jones — who has lived in our village for 20 years — is the world Scrabble champion and the national Cluedo champion. 
(dashes used)
• Mark Jones, who has lived in our village for 20 years, is the world Scrabble champion and the national Cluedo champion. 
(commas used)

Dashes tend to be used when there are other commas in the sentence and when brackets would seem a little too informal. For example:

• Last week, Dr Mark Jones — a resident of Bexley since he graduated from Bexley Secondary School in 1990 — was crowned, for the second year running, the world Scrabble champion. 
(In this example, the writer did not want to use brackets because they would seem too informal and did not want to use commas because there were too many other commas in the sentence.)

You don't need to justify using dashes for parentheses, but just be aware that they can look a little stark.

Note: If you're a stickler for the rules, use an em dash for parentheses. You will get away with en dashes or hyphens.
Read more at http://www.grammar-monster.com/punctuation/using_dashes.htm#v6owOewgBcUeeDvJ.99