August 2018
Intermediate to advanced
227 pages
4h 16m
Chinese
Content preview from 高效R语言编程
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高效数据木匠
｜
121
library("dplyr")
wb_ineq = rename(wb_ineq, code = `Country Code`)
使用冒号分割变量名，可以改变多个列名。
以老版本的数据集演示了如何使
用基本
R
与
dplyr
将冗长、笨拙并低效的名字转换成简短明了的名字。
# dplyr
方式（重命名两个变量）
wb_ineq = rename(wb_ineq,
top10 = `Income share held by highest 10% [SI.DST.10TH.10]`,
bot10 = `Income share held by lowest 10% [SI.DST.FRST.10]`)
# The base R way
（
rename five variables
）
names(wb_ineq)[5:9] = c("top10", "bot10", "gini", "b40_cons", "gdp_percap")
改变列的类
R
对象的类是性能的关键
,
如果使用错误的类（如将数值型当作因子或者字符
处理），这将导致不正确的结果。
数据框所有列的类可通过 str() 函数查询（对
象结构
structure
的缩写），下面代码使用先前加载的不均等数据进行演示
注
1
。
vapply(wb_ineq, class, character(1))
#> Country code Year Year Code top10 bot10
#> "character" ...
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