R语言

变量类型

character – Strings
integer – Integers
numeric – Integers + Fractions 整数和小数
factor – Categorical variable where each level is a category 类型变量
logical – Boolean
complex – Complex numbers 复数

数据类型

vector – A collection of elements of same class 向量
matrix – All columns must uniformly contain only one variable type. 矩阵所有列都包含同一种变量类型
data.frame – The columns can contain different classes. 每一列可以包含不同的类
list – Can hold objects of different classes and lengths 可以包含不同类及不同长度的对象

数据框

数据框是一种很便于进行数据分析的数据对象，R读取csv文件时也是以数据框形式读取的，可用向量创建数据框，R语言也有很多内置的数据框格式数据集#下面一些基本操作代码会经常用到 class(airquality) # get class sapply(airquality, class) # get class of all columns str(airquality) # structure summary(airquality) # summary of airquality head(airquality) # view the first 6 obs fix(airquality) # view spreadsheet like grid rownames(airquality) # row names colnames(airquality) # columns names nrow(airquality) # number of rows ncol(airquality) # number of columns cbind(myDf1, myDf2) # columns append DFs with same no. rows rbind(myDf1, myDf1) # row append DFs with same no. columns