packageDescription(utils)
packageDescription()所属R语言包：utils
Package Description
包装说明
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Parses and returns the "DESCRIPTION" file of a package.
解析和返回DESCRIPTION文件包。
用法----------Usage----------
packageDescription(pkg, lib.loc = NULL, fields = NULL,
drop = TRUE, encoding = "")
packageVersion(pkg, lib.loc = NULL)
参数----------Arguments----------
参数：pkg
a character string with the package name.
与包名称的字符串。
参数：lib.loc
a character vector of directory names of R libraries, or NULL. The default value of NULL corresponds to all libraries currently known. If the default is used, the loaded packages are searched before the libraries.
特征向量的研发图书馆的目录名，或NULL。默认值的NULL对应于目前已知的所有库。如果使用默认值，装包库前搜索。
参数：fields
a character vector giving the tags of fields to return (if other fields occur in the file they are ignored).
字符向量领域的标签返回（如果发生在他们被忽略的文件等领域）。
参数：drop
If TRUE and the length of fields is 1, then a single character string with the value of the respective field is returned instead of an object of class "packageDescription".
如果TRUE长度fields1，然后各自领域的价值与单个字符串返回，而不是一个对象类"packageDescription"。
参数：encoding
If there is an Encoding field, to what encoding should re-encoding be attempted? If NA, no re-encoding. The other values are as used by iconv, so the default "" indicates the encoding of the current locale.
如果有一个Encoding场，什么编码重新编码进行尝试？如果NA，无需重新编码。其他值iconv，所以默认的""表示当前locale的编码。
Details
详情----------Details----------
A package will not be "found" unless it has a "DESCRIPTION" file which contains a valid Version field. Different warnings are given when no package directory is found and when there is a suitable directory but no valid "DESCRIPTION" file.
包不会被“发现”，除非它有一个DESCRIPTION文件，其中包含一个有效的Version领域。没有包目录中发现，当有一个合适的目录，但没有有效的DESCRIPTION文件时，给出不同的警告。
An attached environment named to look like a package (e.g. package:utils2) will be ignored.
一个附加的环境看起来像一个包（例如package:utils2）将被忽略。
packageVersion() is a convenience shortcut, allowing things like if (packageVersion("MASS") < "7.3") { do.things } .
packageVersion()是一个方便快捷，让喜欢if (packageVersion("MASS") < "7.3") { do.things } 的东西。
值----------Value----------
If a "DESCRIPTION" file for the given package is found and can successfully be read, packageDescription returns an object of class "packageDescription", which is a named list with the values of the (given) fields as elements and the tags as names, unless drop = TRUE.
“DESCRIPTION给定的包文件，如果被发现，并可以成功地读取，packageDescription返回一个类的对象"packageDescription"，这是一个值的命名列表（）作为名称的元素和标签领域，除非drop = TRUE。
If parsing the "DESCRIPTION" file was not successful, it returns a named list of NAs with the field tags as names if fields is not null, and NA otherwise.
如果解析DESCRIPTION文件没有成功，它返回字段标签作为名字命名了NA的名单，如果fields是不是null，NA 否则。
packageVersion() returns a (length-one) object of class "package_version".
packageVersion()类"package_version"返回一个（长度）的对象。
参见----------See Also----------
read.dcf
read.dcf
举例----------Examples----------
packageDescription("stats")
packageDescription("stats", fields = c("Package", "Version"))
packageDescription("stats", fields = "Version")
packageDescription("stats", fields = "Version", drop = FALSE)
if(packageVersion("MASS") < "7.3")
message("you need to update 'MASS'")
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 20:44:11
