How to Extract data from dataframe in R?

Extracting data from Data Frame

The data of the data frame is very crucial for us. To manipulate the data of the data frame, it is essential to extract it from the data frame. We can extract the data in three ways which are as follows:

  1. We can extract the specific columns from a data frame using the column name.
  2. We can extract the specific rows also from a data frame.
  3. We can extract the specific rows corresponding to specific columns.

Let’s see an example of each one to understand how data is extracted from the data frame with the help these ways.

Extracting the specific columns from a data frame

Example

# Creating the data frame.  
emp.data<- data.frame(  
employee_id = c (1:5),   
employee_name= c("Shubham","Arpita","Nishka","Gunjan","Sumit"),  
sal = c(623.3,515.2,611.0,729.0,843.25),   
  
starting_date = as.Date(c("2012-01-01", "2013-09-23", "2014-11-15", "2014-05-11",  
      "2015-03-27")),  
stringsAsFactors = FALSE  
)  
# Extracting specific columns from a data frame       
final <- data.frame(emp.data$employee_id,emp.data$sal)  
print(final)  

Output

emp.data.employee_idemp.data.sal
1                    		1       623.30
2                    		2       515.20
3          			        3       611.00
4                    		4       729.00
5                    		5       843.25

Extracting the specific rows from a data frame
Example

# Creating the data frame.  
emp.data<- data.frame(  
employee_id = c (1:5),   
employee_name = c("Shubham","Arpita","Nishka","Gunjan","Sumit"),  
sal = c(623.3,515.2,611.0,729.0,843.25),   
  
starting_date = as.Date(c("2012-01-01", "2013-09-23", "2014-11-15", "2014-05-11",  
      "2015-03-27")),  
stringsAsFactors = FALSE  
)  
# Extracting first row from a data frame      
final <- emp.data[1,]  
print(final)  
  
  
# Extracting last two row from a data frame       
final <- emp.data[4:5,]  
print(final)  

Output

employee_id  employee_name    sal       starting_date
1          1           Shubham       623.3        2012-01-01

   employee_id  employee_name    sal      starting_date
4         4          Gunjan        729.00       2014-05-11
5         5          Sumit         843.25       2015-03-27

Extracting specific rows corresponding to specific columns
Example

# Creating the data frame.  
emp.data<- data.frame(  
employee_id = c (1:5),   
employee_name = c("Shubham","Arpita","Nishka","Gunjan","Sumit"),  
sal = c(623.3,515.2,611.0,729.0,843.25),   
  
starting_date = as.Date(c("2012-01-01", "2013-09-23", "2014-11-15", "2014-05-11",  
      "2015-03-27")),  
stringsAsFactors = FALSE  
)  
# Extracting 2nd and 3rd row corresponding to the 1st and 4th column      
final <- emp.data[c(2,3),c(1,4)]  
print(final)  

Output

employee_id   starting_date
2           2           2013-09-23
3           3           2014-11-15