Ampersand
Encyclopedia
An ampersand is a logogram
representing the conjunction
word "and". The symbol is a ligature of the letters in et, Latin
for "and".
of the phrase "and per se and", meaning "and [the symbol which] by itself [is] and".
Traditionally, in English-speaking schools when reciting the alphabet
, any letter that could also be used as a word in itself ("A", "I", and, at one point, "O") was preceded by the Latin expression per se (Latin for "by itself"). Also, it was common practice to add at the end of the alphabet the "&" sign as the 27th letter, pronounced and. Thus, the recitation of the alphabet would end in: "X, Y, Z and per se and". This last phrase was routinely slurred to "ampersand" and the term crept into common English usage by around 1837.
Through popular etymology, it has been claimed that André-Marie Ampère
used the symbol in his widely read publications, and that people began calling the new shape "Ampère's and".
The ampersand can be traced back to the 1st century A.D. and the Old Roman cursive
, in which the letters E and T occasionally were written together to form a ligature (figure 1). In the later and more flowing New Roman Cursive, ligatures of all kinds were extremely common; figure 2 and 3 from the middle of 5th century are both examples of how the et-ligature could look in this script. However, during the following development of the Latin script that led up to the Carolingian minuscule
(7th century), while the use of ligatures in general diminished, the et-ligature continued to be used and gradually became more stylized and less revealing of its origin (figures 4–6).
The modern italic type
ampersand is a kind of et-ligature that goes back to the cursive scripts developed during the Renaissance
. After the advent of printing
in Europe in 1455, printers made extensive use of both the italic and Roman ampersands. Since the ampersand's roots go back to Roman times, many languages that use a variation of the Latin alphabet
make use of it.
The ampersand often appeared as a letter at the end of the Latin alphabet, as for example in Byrhtferð
list of letters from 1111. Similarly, & was regarded as the 27th letter of the English alphabet
, as used by children (in the USA). An example may be seen in M. B. Moore's 1863 book The Dixie Primer, for the Little Folks. In her 1859 novel Adam Bede
, George Eliot
refers to this when she makes Jacob Storey say, "He thought it[Z] had only been put to finish off th' alphabet like; though ampusand would ha' done as well, for what he could see."
The ampersand should not be confused with the Tironian "et"
(“⁊”), which is a symbol similar to the numeral 7. Both symbols have their roots in the classical antiquity, and both signs were used up through the Middle Ages as a representation for the Latin word "et" ("and"). However, while the ampersand was in origin a common ligature in the everyday script, the Tironian "et" was part of a highly specialised stenographic shorthand
.
, the ampersand is sometimes simplified as an ε superimposed by a vertical line.
Alternatively, it is sometimes written as a t or a + sign with an added loop, resembling the phonetic symbol for a voiceless alveolar lateral fricative ɬ. This type of ampersand may actually be a rendering of the + sign or of the Tironian "et".
s, particularly law firm
s, architectural firm
s, and stockbroker firms
). In such names, a comma
never follows the word just before the ampersand. When the ampersand forms part of a registered name (e.g. Brown & Watson), it should not be replaced with and.
With the growth of mobile phone
usage and text messaging
, the ampersand is gaining new use in SMS language
both as a representation for the word "and" and in rebus
form, such as "pl&" in place of the word "planned".
The ampersand is also often used when addressing a couple in writing: "Mr. & Mrs. Smith" or "Jane & John".
The ampersand is also used for book and movie titles, such as Harry & Tonto, and in some other proper name
s. In these cases, & is interchangeable with the word and; the distinction between them is mostly aesthetic. However, in film
credits for story, screenplay
, etc., & indicates a closer collaboration than and. The ampersand is used by the Writers Guild of America
to denote when two writers collaborated on a specific script, rather than having rewritten another writer's work. In screenplays, two authors joined with & collaborated on the script, while two authors joined with and worked on the script at different times and may not have consulted each other at all. In the latter case, they both contributed enough significant material to the screenplay to receive credit but did not work together (more than likely one was hired to rewrite the previous writer's script).
Many of the first role-playing games used the & in their titles along with alliteration: Tunnels & Trolls, Bunnies & Burrows, and most famously Dungeons & Dragons
, which is commonly abbreviated as D&D.
In APA style
, the ampersand is used when citing sources in text such as (Jones & Jones, 2005). In the list of references, an ampersand precedes the last author's name when there is more than one author. (This does not apply to MLA
style, which calls for the "and" to be spelled.)
The phrase et cetera
("and so forth"), usually written as etc. can be abbreviated &c. representing the combination et + c(etera).
The ampersand can be used to indicate that the "and" in a listed item is a part of the item's name and not a separator (e.g. "Rock, pop, rhythm & blues, and hip hop").
font, the ampersand is rendered as &. The "et" ligature is easily noticed.
The character
is Unicode
, this is inherited from the same value in ASCII
.
Apart from this, Unicode also has the variants:
On the QWERTY
keyboard layout
it is . It is almost always available on any keyboard layout, sometimes on or . On the AZERTY
keyboard layout it is just .
, the ampersand became a commonly used logical notation for the binary operator or sentential connective AND
. This usage was adopted in computing.
, including C++
, Perl
, and more differentiate between:
In C
, C++
, and Go
, a prefix "&" is a unary operator denoting the address in memory
of the argument, e.g.
In C++
and PHP
, unary prefix & before a formal parameter
of a function denotes pass-by-reference
.
In Fortran
, the ampersand forces the compiler to treat two lines as one. This is accomplished by placing an ampersand at the end of the first line and at the beginning of the second line.
In Common Lisp
, the ampersand is the prefix for lambda list keywords.
Ampersand is the string concatenation operator in many BASIC dialects, AppleScript
, HyperTalk
, and FileMaker
. In the Ada
it applies to all one-dimensional arrays, not just strings.
BASIC-PLUS
on the DEC
PDP-11
uses the ampersand as a short form of the verb PRINT.
Applesoft BASIC
used the ampersand as an internal command, not intended to be used for general programming, that invoked a machine language program in the computer's ROM
.
In some versions of BASIC, unary suffix & denotes a variable is of type long, or 32 bit
s in length.
The ampersand is occasionally used as a prefix to denote a hexadecimal
number, such as
. Some other languages, such as the Monitor
built into ROM on the Commodore 128
, used it to indicate octal
instead, a convention that spread throughout the Commodore community and is now used in the VICE
emulator.
In MySQL
the '&' has dual roles. As well as a logical AND, it additionally serves as the bitwise operator of an intersection between elements.
The ampersand character is used as a special character in at least some versions of the database software originally created in Denmark under the name Navision (the software has since been acquired by Microsoft
). Using this character in either "Text" or "Code" fields could create difficulties for performing certain tasks in Navision, such as filtering records (either by the user or by programming). It is also used as described below to indicate shortcuts in menu items and labels.
Perl
uses the ampersand as a sigil
to refer to subroutines:
, and HTML
, the ampersand is used to introduce an SGML entity
. The HTML and XML encoding for the ampersand character is the entity "&" ' onMouseout='HidePop("86535")' href="/topics/Special_Characters">"amper-amp"
). This creates what is known as the ampersand problem. For instance, when putting URLs or other material containing ampersands into XML format files such as RSS
files the amp; has to be added to the & or they are considered not well formed and computers will be unable to read the files correctly. SGML derived the use from IBM Generalized Markup Language, which was one of many IBM-mainframe languages to use the ampersand to signal a text substitution, eventually going back to System/360 macro assembly language.
In the plain TeX
markup language
, the ampersand is used to mark tabstops. The ampersand itself can be applied in TeX with
fonts replace it with an "E.T." symbol in the cmti#(text italic) fonts, so it can be entered as
In Microsoft Windows
menus, labels and other captions, the ampersand is used to denote the keyboard shortcut for that option (Alt
+ that letter, which appears underlined). A double ampersand is needed in order to display a real ampersand. This convention originated in the first WIN32 api, and is used in Windows Forms
, and is also copied into many other tookits on multiple operating systems.
:
Some Unix shells, like the POSIX standard
s.
(Uniform Resource Locator) syntax allows for a query string
to be appended to a file name in a web address so that additional information can be passed to a script; the question mark
, or query mark, ?, is used to indicate the start of a query string. A query string is usually made up of a number of different name–value pairs, each separated by the ampersand symbol, &. For example, www.example.com/login.php?username=test&password=blank.
But see also "Ampersands in URI attribute values".
Logogram
A logogram, or logograph, is a grapheme which represents a word or a morpheme . This stands in contrast to phonograms, which represent phonemes or combinations of phonemes, and determinatives, which mark semantic categories.Logograms are often commonly known also as "ideograms"...
representing the conjunction
Grammatical conjunction
In grammar, a conjunction is a part of speech that connects two words, sentences, phrases or clauses together. A discourse connective is a conjunction joining sentences. This definition may overlap with that of other parts of speech, so what constitutes a "conjunction" must be defined for each...
word "and". The symbol is a ligature of the letters in et, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "and".
Etymology
The word ampersand is a conflationConflation
Conflation occurs when the identities of two or more individuals, concepts, or places, sharing some characteristics of one another, become confused until there seems to be only a single identity — the differences appear to become lost...
of the phrase "and per se and", meaning "and [the symbol which] by itself [is] and".
Traditionally, in English-speaking schools when reciting the alphabet
Alphabet
An alphabet is a standard set of letters—basic written symbols or graphemes—each of which represents a phoneme in a spoken language, either as it exists now or as it was in the past. There are other systems, such as logographies, in which each character represents a word, morpheme, or semantic...
, any letter that could also be used as a word in itself ("A", "I", and, at one point, "O") was preceded by the Latin expression per se (Latin for "by itself"). Also, it was common practice to add at the end of the alphabet the "&" sign as the 27th letter, pronounced and. Thus, the recitation of the alphabet would end in: "X, Y, Z and per se and". This last phrase was routinely slurred to "ampersand" and the term crept into common English usage by around 1837.
Through popular etymology, it has been claimed that André-Marie Ampère
André-Marie Ampère
André-Marie Ampère was a French physicist and mathematician who is generally regarded as one of the main discoverers of electromagnetism. The SI unit of measurement of electric current, the ampere, is named after him....
used the symbol in his widely read publications, and that people began calling the new shape "Ampère's and".
History
Roman cursive
Roman cursive is a form of handwriting used in ancient Rome and to some extent into the Middle Ages. It is customarily divided into old cursive, and new cursive.- Old Roman cursive :...
, in which the letters E and T occasionally were written together to form a ligature (figure 1). In the later and more flowing New Roman Cursive, ligatures of all kinds were extremely common; figure 2 and 3 from the middle of 5th century are both examples of how the et-ligature could look in this script. However, during the following development of the Latin script that led up to the Carolingian minuscule
Carolingian minuscule
Carolingian or Caroline minuscule is a script developed as a writing standard in Europe so that the Roman alphabet could be easily recognized by the literate class from one region to another. It was used in Charlemagne's empire between approximately 800 and 1200...
(7th century), while the use of ligatures in general diminished, the et-ligature continued to be used and gradually became more stylized and less revealing of its origin (figures 4–6).
The modern italic type
Italic type
In typography, italic type is a cursive typeface based on a stylized form of calligraphic handwriting. Owing to the influence from calligraphy, such typefaces often slant slightly to the right. Different glyph shapes from roman type are also usually used—another influence from calligraphy...
ampersand is a kind of et-ligature that goes back to the cursive scripts developed during the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
. After the advent of printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
in Europe in 1455, printers made extensive use of both the italic and Roman ampersands. Since the ampersand's roots go back to Roman times, many languages that use a variation of the Latin alphabet
Latin alphabet
The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...
make use of it.
The ampersand often appeared as a letter at the end of the Latin alphabet, as for example in Byrhtferð
Byrhtferth
Byrhtferth was a priest and monk who lived at Ramsey Abbey. He had a deep impact on the intellectual life of later Anglo-Saxon England and wrote many computistic, hagiographic, and historical works. He was a leading man of science and best known as the author of many different works...
list of letters from 1111. Similarly, & was regarded as the 27th letter of the English alphabet
English alphabet
The modern English alphabet is a Latin alphabet consisting of 26 letters and 2 ligatures – the same letters that are found in the Basic modern Latin alphabet:...
, as used by children (in the USA). An example may be seen in M. B. Moore's 1863 book The Dixie Primer, for the Little Folks. In her 1859 novel Adam Bede
Adam Bede
Adam Bede, the first novel written by George Eliot , was published in 1859. It was published pseudonymously, even though Evans was a well-published and highly respected scholar of her time...
, George Eliot
George Eliot
Mary Anne Evans , better known by her pen name George Eliot, was an English novelist, journalist and translator, and one of the leading writers of the Victorian era...
refers to this when she makes Jacob Storey say, "He thought it
The ampersand should not be confused with the Tironian "et"
Tironian notes
Tironian notes is a system of shorthand said to have been invented by Cicero's scribe Marcus Tullius Tiro. Tiro's system consisted of about 4,000 signs, somewhat extended in classical times to 5,000 signs. In the European Medieval period, Tironian notes were taught in monasteries and the system...
(“⁊”), which is a symbol similar to the numeral 7. Both symbols have their roots in the classical antiquity, and both signs were used up through the Middle Ages as a representation for the Latin word "et" ("and"). However, while the ampersand was in origin a common ligature in the everyday script, the Tironian "et" was part of a highly specialised stenographic shorthand
Shorthand
Shorthand is an abbreviated symbolic writing method that increases speed or brevity of writing as compared to a normal method of writing a language. The process of writing in shorthand is called stenography, from the Greek stenos and graphē or graphie...
.
Writing the ampersand
In everyday handwritingHandwriting
Handwriting is a person's particular & individual style of writing with pen or pencil, which contrasts with "Hand" which is an impersonal and formalised writing style in several historical varieties...
, the ampersand is sometimes simplified as an ε superimposed by a vertical line.
Alternatively, it is sometimes written as a t or a + sign with an added loop, resembling the phonetic symbol for a voiceless alveolar lateral fricative ɬ. This type of ampersand may actually be a rendering of the + sign or of the Tironian "et".
Usage
The ampersand is now rarely used when writing paragraphs. The main surviving use of the ampersand is in the formal names of businesses (especially firms and partnershipPartnership
A partnership is an arrangement where parties agree to cooperate to advance their mutual interests.Since humans are social beings, partnerships between individuals, businesses, interest-based organizations, schools, governments, and varied combinations thereof, have always been and remain commonplace...
s, particularly law firm
Law firm
A law firm is a business entity formed by one or more lawyers to engage in the practice of law. The primary service rendered by a law firm is to advise clients about their legal rights and responsibilities, and to represent clients in civil or criminal cases, business transactions, and other...
s, architectural firm
Architectural firm
An architectural firm is a company which employs one or more licensed architects and practices the profession of architecture.- History :Architects have existed since early in recorded history. The earliest recorded architects include Imhotep and Senemut . No writings exist to describe how these...
s, and stockbroker firms
Stock broker
A stock broker or stockbroker is a regulated professional broker who buys and sells shares and other securities through market makers or Agency Only Firms on behalf of investors...
). In such names, a comma
Serial comma
The serial comma is the comma used immediately before a coordinating conjunction preceding the final item in a list of three or more items...
never follows the word just before the ampersand. When the ampersand forms part of a registered name (e.g. Brown & Watson), it should not be replaced with and.
With the growth of mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
usage and text messaging
Text messaging
Text messaging, or texting, refers to the exchange of brief written text messages between fixed-line phone or mobile phone and fixed or portable devices over a network...
, the ampersand is gaining new use in SMS language
SMS language
SMS language or textese is a term for the abbreviations and slang most commonly used due to the necessary brevity of mobile phone text messaging, in particular the widespread SMS SMS language or textese (also known as txt-speak, txtese, chatspeak, txt, txtspk, txtk, txto, texting language, txt...
both as a representation for the word "and" and in rebus
Rebus
A rebus is an allusional device that uses pictures to represent words or parts of words. It was a favourite form of heraldic expression used in the Middle Ages to denote surnames, for example in its basic form 3 salmon fish to denote the name "Salmon"...
form, such as "pl&" in place of the word "planned".
The ampersand is also often used when addressing a couple in writing: "Mr. & Mrs. Smith" or "Jane & John".
The ampersand is also used for book and movie titles, such as Harry & Tonto, and in some other proper name
Proper name
"A proper name [is] a word that answers the purpose of showing what thing it is that we are talking about" writes John Stuart Mill in A System of Logic , "but not of telling anything about it"...
s. In these cases, & is interchangeable with the word and; the distinction between them is mostly aesthetic. However, in film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
credits for story, screenplay
Screenplay
A screenplay or script is a written work that is made especially for a film or television program. Screenplays can be original works or adaptations from existing pieces of writing. In them, the movement, actions, expression, and dialogues of the characters are also narrated...
, etc., & indicates a closer collaboration than and. The ampersand is used by the Writers Guild of America
Writers Guild of America
The Writers Guild of America is a generic term referring to the joint efforts of two different US labor unions:* The Writers Guild of America, East , representing TV and film writers East of the Mississippi....
to denote when two writers collaborated on a specific script, rather than having rewritten another writer's work. In screenplays, two authors joined with & collaborated on the script, while two authors joined with and worked on the script at different times and may not have consulted each other at all. In the latter case, they both contributed enough significant material to the screenplay to receive credit but did not work together (more than likely one was hired to rewrite the previous writer's script).
Many of the first role-playing games used the & in their titles along with alliteration: Tunnels & Trolls, Bunnies & Burrows, and most famously Dungeons & Dragons
Dungeons & Dragons
Dungeons & Dragons is a fantasy role-playing game originally designed by Gary Gygax and Dave Arneson, and first published in 1974 by Tactical Studies Rules, Inc. . The game has been published by Wizards of the Coast since 1997...
, which is commonly abbreviated as D&D.
In APA style
APA style
American Psychological Association Style is a set of rules that authors use when submitting papers for publications in APA journals. The APA states that they were developed to assist reading comprehension in the social and behavioral sciences, for clarity of communication, and to "move the idea...
, the ampersand is used when citing sources in text such as (Jones & Jones, 2005). In the list of references, an ampersand precedes the last author's name when there is more than one author. (This does not apply to MLA
The MLA Style Manual
The MLA Style Manual and Guide to Scholarly Publishing is the third edition of The MLA Style Manual, first published by the Modern Language Association of America in 1985...
style, which calls for the "and" to be spelled.)
The phrase et cetera
Et cetera
Et cetera is a Latin expression that means "and other things", or "and so forth". It is taken directly from the Latin expression which literally means "and the rest " and is a loan-translation of the Greek "καὶ τὰ ἕτερα"...
("and so forth"), usually written as etc. can be abbreviated &c. representing the combination et + c(etera).
The ampersand can be used to indicate that the "and" in a listed item is a part of the item's name and not a separator (e.g. "Rock, pop, rhythm & blues, and hip hop").
Encoding and display
In the Trebuchet MSTrebuchet MS
Trebuchet MS is a humanist sans-serif typeface designed by Vincent Connare for the Microsoft Corporation in 1996. It is named after the trebuchet, a medieval catapult...
font, the ampersand is rendered as &. The "et" ligature is easily noticed.
The character
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....
is Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
, this is inherited from the same value in ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
.
Apart from this, Unicode also has the variants:
On the QWERTY
QWERTY
QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...
keyboard layout
Keyboard layout
A keyboard layout is any specific mechanical, visual, or functional arrangement of the keys, legends, or key–meaning associations of a computer, typewriter, or other typographic keyboard....
it is . It is almost always available on any keyboard layout, sometimes on or . On the AZERTY
AZERTY
AZERTY is a specific layout for the characters of the Latin alphabet on typewriter keys and computer keyboards. The layout takes its name from the first six letters to appear on the first row of alphabetical keys...
keyboard layout it is just .
Computing
In the 20th century, following the development of formal logicFormal logic
Classical or traditional system of determining the validity or invalidity of a conclusion deduced from two or more statements...
, the ampersand became a commonly used logical notation for the binary operator or sentential connective AND
Logical conjunction
In logic and mathematics, a two-place logical operator and, also known as logical conjunction, results in true if both of its operands are true, otherwise the value of false....
. This usage was adopted in computing.
Programming languages
Many languages with syntax derived from CC (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, including C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, Perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...
, and more differentiate between:
- & for bitwiseBitwise operationA bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. This is used directly at the digital hardware level as well as in microcode, machine code and certain kinds of high level languages...
AND. (4 & 2) is zero, (4 & 5) is 4. - && for short-circuitMinimal evaluationShort-circuit evaluation, minimal evaluation, or McCarthy evaluation denotes the semantics of some Boolean operators in some programming languages in which the second argument is only executed or evaluated if the first argument does not suffice to determine the value of the expression: when the...
logical ANDLogical conjunctionIn logic and mathematics, a two-place logical operator and, also known as logical conjunction, results in true if both of its operands are true, otherwise the value of false....
. (4 && 2) is true.
In C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, and Go
Go (programming language)
Go is a compiled, garbage-collected, concurrent programming language developed by Google Inc.The initial design of Go was started in September 2007 by Robert Griesemer, Rob Pike, and Ken Thompson. Go was officially announced in November 2009. In May 2010, Rob Pike publicly stated that Go was being...
, a prefix "&" is a unary operator denoting the address in memory
Memory address
A digital computer's memory, more specifically main memory, consists of many memory locations, each having a memory address, a number, analogous to a street address, at which computer programs store and retrieve, machine code or data. Most application programs do not directly read and write to...
of the argument, e.g.
&x, &func, &a[3].In C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
and PHP
PHP
PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document...
, unary prefix & before a formal parameter
Parameter (computer science)
In computer programming, a parameter is a special kind of variable, used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are called arguments...
of a function denotes pass-by-reference
Reference (C++)
In the C++ programming language, a reference is a simple reference datatype that is less powerful but safer than the pointer type inherited from C...
.
In Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
, the ampersand forces the compiler to treat two lines as one. This is accomplished by placing an ampersand at the end of the first line and at the beginning of the second line.
In Common Lisp
Common Lisp
Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard document ANSI INCITS 226-1994 , . From the ANSI Common Lisp standard the Common Lisp HyperSpec has been derived for use with web browsers...
, the ampersand is the prefix for lambda list keywords.
Ampersand is the string concatenation operator in many BASIC dialects, AppleScript
AppleScript
AppleScript is a scripting language created by Apple Inc. and built into Macintosh operating systems since System 7. The term "AppleScript" may refer to the scripting system itself, or to particular scripts that are written in the AppleScript language....
, HyperTalk
HyperTalk
HyperTalk is a high-level, procedural programming language created in 1987 by Dan Winkler and used in conjunction with Apple Computer's HyperCard hypermedia program by Bill Atkinson. The main target audience of HyperTalk was beginning programmers, hence HyperTalk programmers were usually called...
, and FileMaker
FileMaker
FileMaker Pro is a cross-platform relational database application from FileMaker Inc., formerly Claris, a subsidiary of Apple Inc. It integrates a database engine with a GUI-based interface, allowing users to modify the database by dragging new elements into layouts, screens, or forms...
. In the Ada
Ada (programming language)
Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...
it applies to all one-dimensional arrays, not just strings.
BASIC-PLUS
BASIC-PLUS
BASIC-PLUS was an extended dialect of the BASIC programming language developed by Digital Equipment Corporation for use on its RSTS/E time-sharing operating system for the PDP-11 series of 16-bit minicomputers in the early 1970s through the 1980s....
on the DEC
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
uses the ampersand as a short form of the verb PRINT.
Applesoft BASIC
Applesoft BASIC
Applesoft BASIC was a dialect of Microsoft BASIC supplied with the Apple II series of computers. It superseded Integer BASIC and was the BASIC in ROM in all Apple II series computers after the original Apple II model. It was also referred to as FP because of the command used to invoke it instead...
used the ampersand as an internal command, not intended to be used for general programming, that invoked a machine language program in the computer's ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
.
In some versions of BASIC, unary suffix & denotes a variable is of type long, or 32 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s in length.
The ampersand is occasionally used as a prefix to denote a hexadecimal
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
number, such as
&FF for decimal 255, for instance in BBC BASICBBC BASIC
BBC BASIC is a programming language, developed in 1981 as a native programming language for the MOS Technology 6502 based Acorn BBC Micro home/personal computer, mainly by Sophie Wilson. It is a version of the BASIC programming language adapted for a U.K...
. Some other languages, such as the Monitor
Machine code monitor
A machine code monitor is software built into or separately available for various computers, allowing the user to enter commands to view and change memory locations on the machine, with options to load and save memory contents from/to secondary storage.Machine code monitors became something of a...
built into ROM on the Commodore 128
Commodore 128
The Commodore 128 home/personal computer was the last 8-bit machine commercially released by Commodore Business Machines...
, used it to indicate octal
Octal
The octal numeral system, or oct for short, is the base-8 number system, and uses the digits 0 to 7. Numerals can be made from binary numerals by grouping consecutive binary digits into groups of three...
instead, a convention that spread throughout the Commodore community and is now used in the VICE
VICE
The software program VICE, standing for VersatIle Commodore Emulator, is an emulator for Commodore's 8-bit computers, running on Amiga, Unix, MS-DOS, Win32, Mac OS X, OS/2, Acorn RISC OS, and BeOS host machines...
emulator.
In MySQL
MySQL
MySQL officially, but also commonly "My Sequel") is a relational database management system that runs as a server providing multi-user access to a number of databases. It is named after developer Michael Widenius' daughter, My...
the '&' has dual roles. As well as a logical AND, it additionally serves as the bitwise operator of an intersection between elements.
The ampersand character is used as a special character in at least some versions of the database software originally created in Denmark under the name Navision (the software has since been acquired by Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
). Using this character in either "Text" or "Code" fields could create difficulties for performing certain tasks in Navision, such as filtering records (either by the user or by programming). It is also used as described below to indicate shortcuts in menu items and labels.
Perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...
uses the ampersand as a sigil
Sigil (computer programming)
In computer programming, a sigil is a symbol attached to a variable name, showing the variable's datatype or scope. In 1999 Philip Gwyn adopted the term "to mean the funny character at the front of a Perl variable".- Historical context:...
to refer to subroutines:
- In Perl 4 and earlier, it was effectively required to call user-defined subroutines
- In Perl 5, it can still be used to modify the way user-defined subroutines are called
- In Perl 6, the ampersand sigilSigil (computer programming)In computer programming, a sigil is a symbol attached to a variable name, showing the variable's datatype or scope. In 1999 Philip Gwyn adopted the term "to mean the funny character at the front of a Perl variable".- Historical context:...
is only used when referring to a subroutine as an object, never when calling it
Text Markup
In SGML, XMLXML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
, and HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
, the ampersand is used to introduce an SGML entity
SGML entity
In the Standard Generalized Markup Language , an entity is a primitive data type, which associates a string with either a unique alias or an SGML reserved word . Entities are foundational to the organizational structure and definition of SGML documents...
. The HTML and XML encoding for the ampersand character is the entity "&" ' onMouseout='HidePop("86535")' href="/topics/Special_Characters">"amper-amp"
Special Characters
Special characters have been given pronunciations similar to letters and numbers in a radio alphabet. The most common pronunciations originated with users of Unix systems....
). This creates what is known as the ampersand problem. For instance, when putting URLs or other material containing ampersands into XML format files such as RSS
RSS (file format)
RSS is a family of web feed formats used to publish frequently updated works—such as blog entries, news headlines, audio, and video—in a standardized format...
files the amp; has to be added to the & or they are considered not well formed and computers will be unable to read the files correctly. SGML derived the use from IBM Generalized Markup Language, which was one of many IBM-mainframe languages to use the ampersand to signal a text substitution, eventually going back to System/360 macro assembly language.
In the plain TeX
TeX
TeX is a typesetting system designed and mostly written by Donald Knuth and released in 1978. Within the typesetting system, its name is formatted as ....
markup language
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...
, the ampersand is used to mark tabstops. The ampersand itself can be applied in TeX with
\&. The Computer ModernComputer Modern
Computer Modern is the family of typefaces used by default by the typesetting program TeX. It was created by Donald Knuth with his METAFONT program, and was most recently updated in 1992. However, the family font was superseded by CM-Super , the latest release dating 2008...
fonts replace it with an "E.T." symbol in the cmti#(text italic) fonts, so it can be entered as
{\it\&} in running text when using the default (Computer Modern) fonts.In Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
menus, labels and other captions, the ampersand is used to denote the keyboard shortcut for that option (Alt
Alt key
The Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...
+ that letter, which appears underlined). A double ampersand is needed in order to display a real ampersand. This convention originated in the first WIN32 api, and is used in Windows Forms
Windows Forms
Windows Forms is the name given to the graphical application programming interface included as a part of Microsoft .NET Framework, providing access to native Microsoft Windows interface elements by wrapping the extant Windows API in managed code...
, and is also copied into many other tookits on multiple operating systems.
Unix shells
Some Unix shells use the ampersand as a metacharacterMetacharacter
A metacharacter is a character that has a special meaning to a computer program, such as a shell interpreter or a regular expression engine.-Examples:...
:
Some Unix shells, like the POSIX standard
sh shell, use the ampersand to execute a process in the background and to duplicate file descriptorFile descriptor
In computer programming, a file descriptor is an abstract indicator for accessing a file. The term is generally used in POSIX operating systems...
s.
- In Bash, the ampersand can separate words, control the command history, duplicate file descriptors, perform logical operations, control jobs, and participate in Regular expressionRegular expressionIn computing, a regular expression provides a concise and flexible means for "matching" strings of text, such as particular characters, words, or patterns of characters. Abbreviations for "regular expression" include "regex" and "regexp"...
s.
Web standards
The generic URLUniform Resource Locator
In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....
(Uniform Resource Locator) syntax allows for a query string
Query string
In World Wide Web, a query string is the part of a Uniform Resource Locator that contains data to be passed to web applications such as CGI programs....
to be appended to a file name in a web address so that additional information can be passed to a script; the question mark
Question mark
The question mark , is a punctuation mark that replaces the full stop at the end of an interrogative sentence in English and many other languages. The question mark is not used for indirect questions...
, or query mark, ?, is used to indicate the start of a query string. A query string is usually made up of a number of different name–value pairs, each separated by the ampersand symbol, &. For example, www.example.com/login.php?username=test&password=blank.
But see also "Ampersands in URI attribute values".