Reading the CSV file into Data frames in R

Here you can check the default working directory using getwd() function and you can also change the directory using the function setwd().

>getwd() #Shows the default working directory 

---->   "C:/Users/Dell/Documents"

> setwd("C:\Users\Dell\Documents\R-test data") #to set the new working Directory

> getwd() #you can see the updated working directory

---> "C:/Users/Dell/Documents/R-test data"

After the setting of the working path, you need to import the data set or a CSV file as shown below.

> readfile <- read.csv("testdata.txt")

Execute the above line of code in R studio to get the data frame as shown below.

To check the class of the variable ‘readfile’, execute the below code.

> class(readfile)

---> "data.frame"            

In the above image you can see the data frame which includes the information of student names, their ID’s, departments, gender and marks.

After getting the data frame, you can now analyse the data. You can extract particular information from the data frame.

To extract the highest marks scored by students,

>marks <- max(data$Marks.Scored) #this will give you the highest marks

#To extract the details of a student who scored the highest marks,

> data <- read.csv("traindata.csv")

> Marks <- max(data$Marks.Scored)

> retval <- subset(data, Marks.Scored == max(Marks.Scored))   #This will
 extract the details of the student who secured highest marks 

> View(retval)

To extract the details of the students who are in studying in ‘chemistry’ Dept,

> readfile <- read.csv("traindata.csv")

> retval <- subset( data, Department == "chemistry")  # This will extract the student details who are in Biochemistry department 
 
> View(retval)