Learning Objectives

• Importing .CSV Files in R
• Importing .TXT Files in R
• Export Data From R

read.csv( )

To read a CSV file in R, we use read.csv( ) function. To know more about this function, execute the given code in R.

• There are various methods to import a file in R like
  • file.choose() helps you to choose the file. Once you execute the given command in R, you will get options to choose a CSV file from your local machine.
    
    1 data = read.csv(file.choose(), header = TRUE)
  • You can pass the location where your file is located
    
    1 data = read.csv(file = "D:/LungCapData.csv", header = TRUE)

Note: You can set the header as TRUE if your file contains the first row as the names of the variables.

• Similar to the read.csv() function, two more functions help you import data in R.
  • read.table()
  • read.delim()
• Use the help() function in R to know more about these functions
• We can read .xls or .xlsx files in R using the readxl package.
• In the video coming up, the tutor will discuss the following things in the hands-on tutorial:
  • How to import CSV data into R? We will be using the "read.table" function to import comma-separated data into R
  • How to import txt data file into R? You will learn to use the "read.delim" function to import the tab-delimited text file into R
  • You will also learn to use the "file.choose" argument for file location, "header" argument to let R know the data has headers or variable names, and "sep" argument to let R know how the data values are separated.

Import CSV or TXT Data in R

readxl package in R

• The readxl package makes it easy to get data out of Excel and into R and clean up the data before importing, thanks to the dedicated work of those behind readxl - Hadley Wickham and Jenny Bryan!

  ▶︎ With the readxl package in RStudio, you can easily import both xlsx and xls files into R from a local file or a URL

  ▶︎ With this RStudio feature, you can easily rename your dataset before importing data into R

  ▶︎ You can change column data types when importing data into R

  ▶︎ Using RStudio to import Excel data, you can choose which Excel worksheet to import to R

  ▶︎ In addition, you will be able to decide which rows of your Excel file to read into R and skip the first X rows

  ▶︎ We will also be able to limit the number of rows imported into R

  ▶︎ readxl package in RStudio will let you skip columns of data when importing Excel data in R

  ▶︎ There is also an option to deal with the missing values in your excel data file and select NA identifiers when importing data into R

Export Data From R

• The most flexible command to export data from R is write.table()

• You can use the help() function in R to learn more about this command
• Some other commands that are used to export data from R are:
  • write.csv2()
  • write.table()