Page 241 - Data Science class 11
P. 241

6.11.5 extracting Data from Data Frame

            Extract a specific column from a data frame using the column name.

            Example
            Enter the following code snippet:

                # Creating the data frame.
                emp.data <- data.frame(

                   emp_id = c (1:5),
                   emp_name = c("Robert","Dharam","Mini","Sharan","Garima"),
                   salary = c(20000.5,35000.2,60000.0,70000.0,84253.25),
                   start_date = as.Date(c("2011-01-21", "2013-11-03", "2014-01-25", "2014-07-21",
                      "2015-05-17")),
                   stringsAsFactors = FALSE
                )
                # Extract Specific columns.
                result <- data.frame(emp.data$emp_name,emp.data$salary)

                print(result)
            On execution of the above code, the following result is shown:



























            Extracting the first two rows and then all columns
            Example

            Enter the following code snippet:

                # Creating the data frame.
                emp.data <- data.frame(
                   emp_id = c (1:5),

                   emp_name = c("Robert","Dharam","Mini","Sharan","Garima"),
                   salary = c(20000.5,35000.2,60000.0,70000.0,84253.25),
                   start_date = as.Date(c("2011-01-21", "2013-11-03", "2014-01-25", "2014-07-21",
                      "2015-05-17")), stringsAsFactors = FALSE)


                                                                                         Programming with R    239
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