download.packages(utils)
download.packages()所属R语言包：utils
Download Packages from CRAN-like Repositories
从CRAN上，像仓库下载软件包
译者：生物统计家园网 机器人LoveR
描述----------Description----------
These functions can be used to automatically compare the version numbers of installed packages with the newest available version on the repositories and update outdated packages on the fly.
这些功能可用于自动比较库提供最新版本的安装包的版本号和更新过时的包上的苍蝇。
用法----------Usage----------
download.packages(pkgs, destdir, available = NULL,
repos = getOption("repos"),
contriburl = contrib.url(repos, type),
method, type = getOption("pkgType"), ...)
参数----------Arguments----------
参数：pkgs
character vector of the names of packages whose latest available versions should be downloaded from the repositories.
字符向量包的最新可用版本的名称应当从资料库下载。
参数：destdir
directory where downloaded packages are to be stored.
目录下载的软件包将被储存起来。
参数：available
an object as returned by available.packages listing packages available at the repositories, or NULL which makes an internal call to available.packages.
一个对象作为返回available.packages上市软件包仓库，或NULL这使得available.packages内部通话。
参数：repos
character vector, the base URL(s) of the repositories to use, i.e., the URL of the CRAN master such as "http://cran.r-project.org" or its Statlib mirror, "http://lib.stat.cmu.edu/R/CRAN".
特征向量，基本URL（S）的仓库使用，即CRAN的大师，如"http://cran.r-project.org"或者其Statlib的镜子，"http://lib.stat.cmu.edu/R/CRAN"的URL。
参数：contriburl
URL(s) of the contrib sections of the repositories. Use this argument only if your repository mirror is incomplete, e.g., because you burned only the "contrib" section on a CD. Overrides argument repos.
URL（S）仓库的contrib部分。使用此参数，只有当你的资料库镜像是不完整的，例如，因为你烧在CD上只有contrib节。覆盖参数repos。
参数：method
Download method, see download.file.
下载方法，请参阅download.file。
参数：type
character string, indicate which type of packages: see install.packages.
字符串，表明包的类型：install.packages。
参数：...
additional arguments to be passed to download.file.
额外的参数被传递到download.file。
Details
详情----------Details----------
download.packages takes a list of package names and a destination directory, downloads the newest versions and saves them in destdir. If the list of available packages is not given as argument, it is obtained from repositories. If a repository is local, i.e. the URL starts with "file:", then the packages are not downloaded but used directly. Both "file:" and "file:///" are allowed as prefixes to a file path. Use the latter only for URLs: see url for their interpretation. (Other forms of file:// URLs are not supported.)
download.packages需要一个包名和目标目录的列表，下载最新版本，并保存在destdir。如果可用的软件包列表不作为参数，它从仓库获得。如果一个版本库是本地的，即URL"file:"开始，然后包不下载，但直接使用。既"file:"和"file:///"允许文件路径前缀。网址为只使用后者：他们的解释url。 （其他形式的file://网址是不支持。）
值----------Value----------
A two-column matrix of names and destination file names of those packages successfully downloaded. If packages are not available or there is a problem with the download, suitable warnings are given.
成功下载这些软件包的名称和目标文件名的一个两列的矩阵。如果包不使用或下载有一个问题，给予适当的警告。
参见----------See Also----------
available.packages, contrib.url.
available.packages，contrib.url。
The main use is by install.packages.
主要使用的是install.packages。
See download.file for how to handle proxies and other options to monitor file transfers.
看到download.file如何处理代理和其他选项来监视文件传输。
The "R Installation and Administration" manual for how to set up a repository.
“R安装和管理的手册为如何建立一个仓库。
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-2-16 18:20:17
