Inspecting your data in R

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Overview

Questions

• How many rows and columns are in my data frame?
• What are the names of the columns in my data frame?
• How can I look up parts of my data frame?
• How do I find out what the internal structure of my data frame is?

Objectives

• Determine the number of rows and columns in a data frame
• Look up the names of the columns in a data frame
• Pull up sections of a data frame
• Inspect the internal structure of a data frame

Key Points

• Inspect the dimensions of a data frame using dim()
• Find out the number of rows and columns of a data frame using nrow and rcol
• Use colnames() and rownames() to display column and row names respectively
• Use head() to view the first six rows of a data frame
• Look at data in a specific column by using the $ operator
• Use [] to subset data from a data frame
• Use str() to inspect the internal structure of the data frame