Data Frame: This is the most commonly used member of data types family. It is used to store tabular data. It is different from matrix. In a matrix, every element must have same class. But, in a data frame, you can put list of vectors containing different classes. This means, every column of a data frame acts like a list. Every time you will read data in R, it will be stored in the form of a data frame. Hence, it is important to understand the majorly used commands on data frame:
df <- data.frame(name = c("ash","jane","paul","mark"), score = c(67,56,87,91))
df[1:2,2] <- NA #injecting NA at 1st, 2nd row and 2nd column of df