R is a language and environment for statistical computing and graphics. It is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories (formerly AT&T, now Lucent Technologies) by John Chambers and colleagues. R can be considered as a different implementation of S. There are some important differences, but much code written for S runs unaltered under R.$ |# |' ]- d- h6 F' J' ^
R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, ...) and graphical techniques, and is highly extensible. The S language is often the vehicle of choice for research in statistical methodology, and R provides an Open Source route to participation in that activity. 0 g q" c7 [/ y" ?One of R's strengths is the ease with which well-designed publication-quality plots can be produced, including mathematical symbols and formulae where needed. Great care has been taken over the defaults for the minor design choices in graphics, but the user retains full control. ( G7 Q* e; x, I( Q/ K( ]8 Y- _6 C0 iR is available as Free Software under the terms of the Free Software Foundation's GNU General Public License in source code form. It compiles and runs on a wide variety of UNIX platforms and similar systems (including FreeBSD and Linux), Windows and MacOS.0 H/ q Q6 ~, ]* P+ Z2 [" U
The R environment' r6 r: s$ |' a( [8 f3 p7 H
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R is an integrated suite of software facilities for data manipulation, calculation and graphical display. It includes! {9 h e" f, t2 y) J b
an effective data handling and storage facility, 7 T" A# Q5 d8 Z) L1 \) S! \6 Ta suite of operators for calculations on arrays, in particular matrices,% u( l0 l! z3 {( r
a large, coherent, integrated collection of intermediate tools for data analysis,+ s/ N( B& d! j2 p" X9 c1 S7 c( m: z
graphical facilities for data analysis and display either on-screen or on hardcopy, and3 g/ B7 z) k ^5 S+ e
a well-developed, ** and effective programming language which includes conditionals, loops, user-defined recursive functions and input and output facilities. ) B; E4 `: z0 V! [$ w/ c8 e& ?The term "environment" is intended to characterize it as a fully planned and coherent system, rather than an incremental accretion of very specific and inflexible tools, as is frequently the case with other data analysis software. 7 }( B0 a# z" E9 @# W3 AR, like S, is designed around a true computer language, and it allows users to add additional functionality by defining new functions. Much of the system is itself written in the R dialect of S, which makes it easy for users to follow the algorithmic choices made. For computationally-intensive tasks, C, C++ and Fortran code can be linked and called at run time. Advanced users can write C code to manipulate R objects directly. * O9 r2 k* [2 U ^3 | ~" L3 [Many users think of R as a statistics system. We prefer to think of it of an environment within which statistical techniques are implemented. R can be extended (easily) via packages. There are about eight packages supplied with the R distribution and many more are available through the CRAN family of Internet sites covering a very wide range of modern statistics.# c6 G% y) o& B9 |. E5 H
R has its own LaTeX-like documentation format, which is used to supply comprehensive documentation, both on-line in a number of formats and in hardcopy.5 I9 |' D( f- G0 Z$ U" D+ f+ I
R软件是一种用于统计计算和绘图的语言环境。它遵照GNU计划,且与S语言环境类似。S语言由贝尔实验室工作者John Chambers及其同事开发。R可被认为是S语言的另一种实现,虽然它们之间有些重要区别,但是许多S中的代码可以毫无修改地在R中运行。# q$ l; D* V7 ^! T' f0 o
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R软件不仅提供了丰富的统计与绘图技术,包括线性与非线性建模,经典统计检测,时间序列分析,分类,聚类等,而且具有高度可扩展性。S语言是统计方法 轮研究方面的得力工具,而R则以开放源码的方式促使人们更好的加入其中。 . y: l& u- J, L6 e: ^5 j" _ 9 v5 G% b! I- c6 [& OR的优势之一在于应用简洁的操作即可输出精巧优质的图像,其中甚至包括数学符号和公式。R精心考虑了控制图像因素的每一个预设值,工作人员尽管可以随心所欲地改变其值,但少许的改动已经足够了。( n" f0 X+ s3 I
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R遵循自由软件基金会GNU协议,是一款代码开源软件。它可在UNIX平台及其类似系统(包括FreeBSD和Linux),Windows和Mac系统上编译与运行。7 l, m; x' r+ E, O
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R的运行环境 ' p, F3 \- X: j2 A) H4 V/ z7 E, _1 a' Z, _: J
R是一套完整的数据处理、计算和制图软件系统。其功能包括:数据存储和处理系统;数组运算工具(其向量、矩阵运算方面功能尤其强大);完整连贯的统计分析工具;优秀的统计制图功能;简便而强大的编程语言(条件控制,循环语句,自定义递归函数以及输入输出设备)。8 n2 z' ^3 c) Y; Q
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使用“环境”(Environment)一词意在区别于其它为具体问题而设计(因而应用有限)的数据分析软件,R是完整的、一致连贯的系统。/ G% c- U$ h9 c, m4 Q( x
, @! e' f _. W6 s& M" d" c U: s. N正如S,R允许用户借助高级计算机语言编写函数以扩充其功能。因此用户更容易理解其选择的算法。对于复杂的计算工作,R可以在运行时调用C,C++或Fortran代码。高级用户可以编写C代码直接操纵R中的对象。 , H, B- k: J2 f; M(译者注:以上仅供参考!)