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R Introduction: Part I
course content

Course Content

R Introduction: Part I

R Introduction: Part I

1. Basic Syntax and Operations
Why R?Basic ArithmeticUsing the print() Function Comments in RInteger Division and RemaindersExponentiationcat() FunctionVariablesRevenue CalculationAssignment Operators
2. Basic Data Types and Vectors
Data TypesNumbersType ConversionLogical TypesVectorsLabeling VectorsIndexing in VectorsModifying VectorsDeleting Elements from VectorsArithmetic Operations with Vectors
3. Factors
What is a Factor?Indexing in FactorsLevelsCounting ValuesGrouping Numeric DataGrades Summary

bookIndexing in Vectors

Great! Now you understand how to create a vector and assign names to its values.

To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.

Now, let’s revisit the grades example:

We'll extract the grade for Math and the grade for Literature.


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the first grade
grades[1]
# Output Literature grade
grades['Literature']
copy

It's also possible to access multiple elements simultaneously:


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the second and the third grades
grades[c(2,3)]
# Output Math and Physics grades
grades[c('Math','Physics')]
copy

Task

Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.

  1. Retrieve the price of 'Armchair' using its name rather than its index.
  2. Retrieve the prices for both the 'Dining table' and 'Dining chair' using their indices.

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Section 2. Chapter 7
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bookIndexing in Vectors

Great! Now you understand how to create a vector and assign names to its values.

To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.

Now, let’s revisit the grades example:

We'll extract the grade for Math and the grade for Literature.


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the first grade
grades[1]
# Output Literature grade
grades['Literature']
copy

It's also possible to access multiple elements simultaneously:


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the second and the third grades
grades[c(2,3)]
# Output Math and Physics grades
grades[c('Math','Physics')]
copy

Task

Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.

  1. Retrieve the price of 'Armchair' using its name rather than its index.
  2. Retrieve the prices for both the 'Dining table' and 'Dining chair' using their indices.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 2. Chapter 7
toggle bottom row

bookIndexing in Vectors

Great! Now you understand how to create a vector and assign names to its values.

To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.

Now, let’s revisit the grades example:

We'll extract the grade for Math and the grade for Literature.


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the first grade
grades[1]
# Output Literature grade
grades['Literature']
copy

It's also possible to access multiple elements simultaneously:


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the second and the third grades
grades[c(2,3)]
# Output Math and Physics grades
grades[c('Math','Physics')]
copy

Task

Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.

  1. Retrieve the price of 'Armchair' using its name rather than its index.
  2. Retrieve the prices for both the 'Dining table' and 'Dining chair' using their indices.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Great! Now you understand how to create a vector and assign names to its values.

To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.

Now, let’s revisit the grades example:

We'll extract the grade for Math and the grade for Literature.


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the first grade
grades[1]
# Output Literature grade
grades['Literature']
copy

It's also possible to access multiple elements simultaneously:


              
1234567

            
grades <- c(80, 75, 95, 100) # Vector of grades
# Assign names to values of grades
names(grades) <- c('Math', 'Physics', 'English', 'Literature')
# Output the second and the third grades
grades[c(2,3)]
# Output Math and Physics grades
grades[c('Math','Physics')]
copy

Task

Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.

  1. Retrieve the price of 'Armchair' using its name rather than its index.
  2. Retrieve the prices for both the 'Dining table' and 'Dining chair' using their indices.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Section 2. Chapter 7
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
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