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From Wikipedia, the free encyclopedia

Basic Latin alphabet
Aa Bb Cc Dd    
Ee Ff Gg Hh
Ii Jj Kk Ll Mm Nn
Oo Pp Qq Rr Ss Tt
Uu Vv Ww Xx Yy Zz

R is the eighteenth letter of the modern Latin alphabet. Its name in English (pronounced /ˈɑr/) is spelled ar, plural ars;[1] its name in Hiberno-English is or /ˈɔr/.



Egyptian hieroglyph
Proto-Semitic R Phoenician
Etruscan R Greek
Later Etruscan R
Proto-semiticR-01.png PhoenicianR-01.png EtruscanR-01.svg Rho uc lc.svg EtruscanR-02.svg

The original Semitic letter was probably inspired by an Egyptian hieroglyph for "head", pronounced t-p in Egyptian, but it was used for /r/ by Semites because in their language, the word for "head" was Rêš (also the name of the letter). It developed into Greek Ρ ῥῶ (Rhô) and Latin R. It is likely that some Etruscan and Western Greek forms of the letter added the extra stroke to distinguish it from a later form of the letter P.

The minuscule (lower-case) form of r developed through several variations on the capital form. In handwriting it was common not to close the bottom of the loop but continue into the leg, saving an extra pen stroke. The loop-leg stroke shortened into the simple arc used today. Another minuscule, r rotunda (ꝛ), kept the loop-leg stroke but dropped the vertical stroke. It fell out of use around the 18th century.


The letter R represents a rhotic consonant in many languages, as shown in the table below. The International Phonetic Alphabet uses several variations of the letter to represent the different rhotic consonsants; [r] represents the alveolar trill.

Alveolar trill [r] Listen Arabic, Armenian, Bulgarian, some dialects of British English or in emphatic speech, Finnish, German in some dialects, Hungarian, Icelandic, Italian, Czech, Lithuanian, Latin, Norwegian, Polish, Catalan, Portuguese (traditional European form), Romanian, Russian, Scots, Spanish and Albanian 'rr', Swedish, Welsh, in standard Dutch, Galician
Alveolar approximant [ɹ] Listen English (most varieties), Dutch in some Dutch dialects (in specific positions of words), Faroese
Alveolar flap / Alveolar tap [ɾ] Listen Greek, Hindi 'र', Korean 'ㄹ' (also realised as [l] or [ɭ]), Portuguese, Catalan, Spanish and Albanian 'r', Turkish, Italian, Quechua, Galician, Leonese
Alveolar lateral flap [ɺ] Listen Japanese
Voiced retroflex fricative [ʐ] Listen Mandarin as an allophone, Spanish used as an allophone of [r] in some South American accents.
Retroflex approximant [ɻ] Listen some varieties of American English, Mandarin as an allophone
Retroflex flap [ɽ] Listen Hindi 'ड़', sometimes Scottish English
Uvular trill [ʀ] Listen Arabic, German stage standard; some Dutch dialects (mainly in Belgium), Swedish in Southern Sweden, Norwegian in western and southern parts
Voiced uvular fricative [ʁ] Listen German, Danish, French, Modern Hebrew, Portuguese

Other languages may use the letter r in their alphabets (or Latin transliterations schemes) to represent rhotic consonants different from the alveolar trill. In Haitian Creole, it represents a sound so weak that it is often written interchangeably with w, eg. Kweyol for Kreyol.

Dog's Letter

The letter R is sometimes referred to as the littera canina (canine letter). This phrase has Latin origins: the Latin R was trilled so it sounds like a growling dog. A good example of a trilling R is the Spanish word for dog, perro. [2] In William Shakespeare's Romeo and Juliet, such a reference is made by Juliet's nurse in Act 2, scene 4, when she calls the letter R "the dog's name." The reference is also found in Ben Jonson's English Grammar.[3]

Codes for computing

Alternative representations of R
NATO phonetic Morse code
Romeo ·–·
ICS Romeo.svg Semaphore Romeo.svg ⠗
Signal flag Flag semaphore Braille

In Unicode, the capital R is codepoint U+0052 and the lower case r is U+0072.

The ASCII code for capital R is 82 and for lowercase r is 114; or in binary 01010010 and 01110010, correspondingly.

The EBCDIC code for capital R is 217 and for lowercase r is 153.

The numeric character references in HTML and XML are "R" and "r" for upper and lower case respectively.

See also


  1. ^ "R" Oxford English Dictionary, 2nd edition (1989); "ar," op. cit.
  2. ^ A Word A Day: Dog's letter
  3. ^ Shakespeare, William; Horace Howard Furness, Frederick Williams (1913). Romeo and Juliet. Lippincott. p. 189. 
The basic modern Latin alphabet
Aa Bb Cc Dd Ee Ff Gg Hh Ii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww Xx Yy Zz
Letter R with diacritics

history palaeography derivations diacritics punctuation numerals Unicode list of letters ISO/IEC 646

Study guide

Up to date as of January 14, 2010
(Redirected to How to use R article)

From Wikiversity


R is a

  • powerful, free and open source, cross-platform, statistical and graphing software package;
  • programming language;
  • software environment for statistical computing.


Downloading R

Visit the R Project home page.


Attention yellow.svg There are many well developed and maintained existing R tutorials on the web, e.g.,

Books that are Helpful When Learning R

An R and S-Plus Companion for Applied Regression
Introductory Statistics with R
Using R for Data Analysis and Graphics: Introduction, Code and Commentary, by J. H. Maindonald (PDF)
An Introduction to R, by W. N. Venables, D. M. Smith, and the R Development Core Team (PDF)

See also

Wikipedia-logo.png Run a search on R at Wikipedia.
Wikibooks-logo-en.svg Wikibooks has a book on the topic of R Programming.

External links


1911 encyclopedia

Up to date as of January 14, 2010
(Redirected to Database error article)

From LoveToKnow 1911

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Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

The Universal Character Set
Basic Latin U+0052



Wikipedia has an article on:



R upper case (lower case r)

  1. The eighteenth letter of the basic modern Latin alphabet.

See also



  1. (physics) roentgen (unit)
  2. (physics) resistance (in electricity)
  3. (genetics) IUPAC 1-letter abbreviation for any purine
  4. (biochemistry) IUPAC 1-letter abbreviation for arginine

See also

Other representations of R:





  1. The eighteenth letter of the English alphabet, preceded by Q and followed by S.



  1. (US politics) Republican
  2. (film certification) restricted
  3. reverse
  4. right (as opposed to left)
  5. (handbells) ring
  6. (baseball, cricket) The statistic reporting the number of runs scored by a player
  7. Thursday

American Sign Language


R (Stokoe R)

  1. The letter R



  • (letter name): IPA: /ɛr/


R (capital, lowercase r)

  1. The eighteenth letter of the Dutch alphabet.

See also

  • Previous letter: Q
  • Next letter: S




Italian Wikipedia has an article on:

Wikipedia it

R m. and f. inv.

  1. The sixteenth letter of the Italian alphabet
  2. The eighteenth letter of the Latin alphabet




  1. Romanus
  2. Rufus



  • IPA: /re/, /er/


R (capital, lowercase r)

  1. The twentieth letter of the Romanian alphabet representing the phoneme /r/. Preceded by P and followed by S.


Slovene Wikipedia has an article on:

Wikipedia sl



R (capital, lowercase r)

  1. The 18th letter of the Slovene alphabet. Preceded by P and followed by S.



R (upper case, lower case r)

  1. The 21st letter of the Spanish alphabet.


Up to date as of January 23, 2010
(Redirected to R Programming article)

From Wikibooks, the open-content textbooks collection

Wikibook Development Stages
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Welcome to the
'R' programming

  • This is a guide to the R programming language[1].
  • Why this R programming wikibook ?
    • You generally have good documentation for each package in 'R' but it is not so easy to find the right package and to compare functions from different packages. For instance you have many functions which export the results to latex and it is not obvious to know which is the best for your needs.
    • One can find many resources and handouts on R programming on the Internet but all these resources are scattered and therefore difficult to find and to compare.
    • The aim of this wikibook is to be the place where anyone can share his/her tricks and knowledge on R.
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    • give useful examples using fake data simulations or R example datasets
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  1. R Development Core Team (2009). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL

Simple English

The Latin alphabet
Aa Bb Cc Dd
Ee Ff Gg Hh Ii Jj
Kk Ll Mm Nn Oo Pp
Qq Rr Ss Tt Uu Vv
Ww Xx Yy Zz

R is the eighteenth (number 18) letter in the English alphabet.

Meanings for R

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