从R中具有可变字符串条件的数据框中提取行

Question

Take iris as the data frame, I want to extract all rows and column variables (Petal.Length,Petal.Width,Sepal.Length,Sepal.Width) that have species as a specific value. eg setosa. it should show 50 entries. I tried aggregate but didnt work. It is the equivalent and of the WHERE clause in SQL.

Answer 1

You are looking for the subset command.

data(iris)

dat<-subset(iris,subset=Species=='setosa')