August 2018
Intermediate to advanced
227 pages
4h 16m
Chinese
Content preview from 高效R语言编程
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高效安装
｜
29
有关将发布的新版本的变动信息，可通过订阅
R
的
RSS
获取。这是非常好的
跟踪新版本的方法。
安装
R
包
大型项目可能需要安装多个包，这种情况下可一次性安装所有需要的包。以
处理稀疏数据的包安装为例，可通过下面代码快速、便捷地安装：
pkgs = c
（
"raster", "leaflet", "rgeos"
）
#
包名
install.packages
（
pkgs
）
上述代码中，使用两行而不是三行代码安装上所有包，降低了键盘输入量。
需要注意的是，可多次使用 pkgs 对象来加载上述的三个包：
inst = lapply
（
pkgs, library, character.only = TRUE
）
#
加载所有包
上述代码中，通过 library(pkg[i]) 将保存在字符串向量中的每个包进行了
加载。我们用 library() 代替 require() 函数的原因是：library() 函数在
加载包时，如该包不存在将报错。
在代码的起始位置加载所有包是良好的习惯，这样确保执行代码前所有依赖
包均安装。将待装包名保存到类似 pkgs 的字符向量对象中是有益的，我们可
以多次调用它们。
安装
R
包及依赖项
一些
R
包有外部依赖（比如可能调用了
R
以外的库）。在类
UNIX
系统中，
最好的方案是在操作系统层面进行安装，不要使用 install.packages。这
样保证了安装
R
包的同时，必须的依赖包得以安装和正确的设置。在基于
Debian
的发行系统（例如
Ubutu
）下，以 r-cran- 开头的包可使用下列形式
搜索安装（可到 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.