R包的安装及dplyr基本包的使用

-本章注重实践

dplyr包的使用.png

library(dplyr)
select(iris,colnames="Sepal.Width")#筛选列#
select(iris,-c(2,3))# 筛选列#
mutate(iris,yyj=iris$Sepal.Length+iris$Sepal.Width)#增加列#
filter(iris,group_by(iris,Species))#筛选行# 
arrange(iris,Species=="setosa")#按照行的条件筛选整个表格数据“
summarise(iris,mean(Sepal.Length),sd(Sepal.Length))#总结参数#
iris%>%group_by(Species)%>%summarise(mean(Sepal.Width),sd(Sepal.Width))#传递符#
count(iris,Species)#统计某一列的unique值#
options(stringsAsFactors = F)#用dplyr处理关系数据#
test1 <- data.frame(x = c('b','e','f','x'), z = c("A","B","C",'D'),stringsAsFactors = F)
test2 <- data.frame(x = c('a','b','c','d','e','f'), y = c(1,2,3,4,5,6),stringsAsFactors = F)
inner_join(test1, test2, by = "x")
left_join(test2, test1, by = 'x')