subset 函数 选择数据框/向量的子集

subset(数据框，条件) 按条件选择子集

 Datafra<-data.frame(name=c(1,2,4,NA,4,5,7),family=c("xiao","ming",NA,NA,"zhou","zheng","li"))
 Datafra

　　

subset(Datafra,name>=1)  

subset(Datafra,name>=1 & family !="NA")  #允许逻辑符

> subset(Datafra,name>=1 & family !="NA",select = name)

subset(Datafra,name>=1 & family !="NA",select = 1)  #搭配select 选择列名/列索引

 df<-subset(Datafra,select = -c(name))  # 减号去除某列

还可以从向量中依条件选择元素 如subset(vec,vec>2) ，默认去除NA