R in Action

R in Action (2nd ed) significantly expands upon this material. Use promo code ria38 for a 38% discount.

Getting Information on a Dataset

There are a number of functions for listing the contents of an object or dataset.

# list objects in the working environment ls()

# list the variables in mydata names(mydata)

# list the structure of mydata str(mydata)

# list levels of factor v1 in mydata levels(mydata$v1)

# dimensions of an object dim(object)

# class of an object (numeric, matrix, data frame, etc) class(object)

# print mydata mydata

# print first 10 rows of mydata head(mydata, n=10)

# print last 5 rows of mydata tail(mydata, n=5)

Try the free first chapter of this course on cleaning data.