Hyphen-minus

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-
Hyphen-minus
Punctuation
apostrophe  '
brackets [ ]  ( )  { }  ⟨ ⟩
colon :
comma ,  ،  
dash ‒  –  —  ―
ellipsis  ...  . . .      
exclamation mark !
full stop, period .
guillemets ‹ ›  « »
hyphen
hyphen-minus -
question mark ?
quotation marks ‘ ’  “ ”  ' '  " "
semicolon ;
slash, stroke, solidus /    
Word dividers
interpunct ·
space     
General typography
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at sign @
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komejirushi, kome, reference mark
multiplication sign ×
number sign, pound, hash #
numero sign
obelus ÷
ordinal indicator º ª
percent, per mil % ‰
pilcrow
plus, minus + −
plus-minus, minus-plus ± ∓
prime    
section sign §
tilde ~
underscore, understrike _
vertical bar, pipe, broken bar |    ¦
Intellectual property
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sound-recording copyright
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؋฿¢$֏ƒ£元 圆 圓 ¥

Uncommon typography
asterism
fleuron, hedera
index, fist
interrobang
irony punctuation
lozenge
tie
Related
In other scripts

The hyphen-minus (-) is a character used in digital documents and computing to represent a hyphen (‐) or a minus sign (−).[1]

It is present in Unicode as code point U+002D - HYPHEN-MINUS; it is also in ASCII with the same value.

Description[edit]

The glyph for the hyphen-minus is not as wide as that of the plus sign.

The use of a single character for both hyphen and minus was a compromise made in the early days of fixed-width typewriters and computer displays.[2] However, in proper typesetting and graphic design, there are distinct characters for hyphens, dashes, and the minus sign. Usage of the hyphen-minus nonetheless persists in many contexts, as it is well-known, easy to enter on keyboards, and in the same location in all common character sets.

As the minus sign[edit]

Most programming languages, restricting themselves to 7-bit ASCII, use the hyphen-minus, rather than the Unicode character U+2212 MINUS SIGN, for denoting subtraction and negative numbers.[3][4]

The minus sign is nominally the same width as the plus sign. In proportional typefaces it is longer than a hyphen. During typesetting a word wrap may also occur following a hyphen-minus, unlike the minus sign proper which is treated as a mathematical symbol. These differences make "-" as a substitute for minus signs undesirable in professional typography.

Command line[edit]

The ASCII hyphen-minus character is also often used when specifying command-line options. The character is usually followed by one or more letters that indicate specific actions. Various implementations of the getopt function to parse command-line options additionally allow the use of two hyphen-minus characters ( -- ) to specify long option names that are more descriptive than their single-letter equivalents. Another use of hyphens is that employed by programs written with pipelining in mind: a single hyphen may be recognized in lieu of a filename, with the hyphen then serving as an indicator that a standard stream, instead of a file, is to be worked with.

Other uses[edit]

On typewriters, it was conventional to use a pair of hyphens to represent an em dash, and this convention is still sometimes used in computer text.

The hyphen-minus is often used to represent an en dash, which may be used to indicate ranges (such as a time range of "2000–2004"), direction (as in "The Los Angeles–London flight"), and other cases of connection. The en dash is normally longer (the width of a letter "n") than a hyphen, though in a fixed-pitch or typewriter font there is no difference. The hyphen connects closely, the en dash less closely, while the em dash (the width of a letter "m") separates.[5]

In some programming languages -- marks beginning of a comment. Likewise, it can occasionally start the signature block.

See also[edit]

References[edit]

  1. ^ Jukka K. Korpela (2006). Unicode explained. O'Reilly. p. 382. ISBN 978-0-596-10121-3.
  2. ^ Fischer, Eric. "The Evolution of Character Codes, 1874-1968" (PDF). Retrieved 16 November 2016.
  3. ^ Ritchie, Dennis (c. 1975). "C Reference Manual" (PDF). Retrieved 7 December 2016.
  4. ^ "Haskell 2010 Language Report" (PDF). Retrieved 7 December 2016.
  5. ^ "Hyphens, En Dashes, Em Dashes". The Chicago Manual of Style Online. Retrieved 25 January 2017.