R 基础 数组

1. 按属性排序

mtcars[order(mpg),] 

升降序

 mtcars[order(mpg, cyl),]

2.apply 

https://stackoverflow.com/questions/4236368/apply-a-function-to-every-row-of-a-matrix-or-a-data-frame

https://www.r-bloggers.com/using-apply-sapply-lapply-in-r/

3.正则表达式及R字符串处理之终结版

http://yphuang.github.io/blog/2016/03/15/regular-expression-and-strings-processing-in-R/

常规正则

http://www.runoob.com/regexp/regexp-syntax.html

4.转变成数字

as.numeric

But, if all the columns needs to changed to numeric, use lapply to loop over the columns and convert to numeric by first converting it to character class as the columns were factor.

lapply(data, function(x) as.numeric(x))

5.R判断！一个元素是否在集合

https://blog.youkuaiyun.com/u011402596/article/details/43938093 ，%in% 

6.R语言Data Frame数据框常用操作, 高级SQL 选择

http://www.cnblogs.com/studyzy/p/R_DataFrame_Operation.html

7.String r 处理包

http://blog.fens.me/r-stringr/

8 画 多个图

matplot(data , type = c(b),col = 1:2)