Lists and Matrices in R Programming

1. Lists

Lists in R can store elements of different data types, such as numbers, strings, and even other lists.

Creating a List

    # Creating a list
    my_list <- list(
      Name = "Alice",
      Age = 25,
      Scores = c(85, 90, 95)
    )
    
    # Printing the list
    print(my_list)

Accessing List Elements

    # Access an element by name
    print(my_list$Name)
    
    # Access an element by index
    print(my_list[[2]])
    
    # Access a specific part of an element (e.g., a vector inside the list)
    print(my_list$Scores[1])

Modifying a List

    # Add a new element to the list
    my_list$Gender <- "Female"
    print(my_list)
    
    # Remove an element from the list
    my_list$Age <- NULL
    print(my_list)

2. Matrices

Matrices in R are two-dimensional arrays that can hold elements of the same data type.

Creating a Matrix

    # Creating a matrix
    my_matrix <- matrix(
      data = 1:9,       # Data values
      nrow = 3,         # Number of rows
      ncol = 3,         # Number of columns
      byrow = TRUE      # Fill the matrix by rows
    )
    
    # Printing the matrix
    print(my_matrix)

Accessing Matrix Elements

    # Access an element by row and column
    print(my_matrix[2, 3])
    
    # Access an entire row
    print(my_matrix[1, ])
    
    # Access an entire column
    print(my_matrix[, 2])

Manipulating a Matrix

    # Add a new row to the matrix
    new_row <- c(10, 11, 12)
    my_matrix <- rbind(my_matrix, new_row)
    print(my_matrix)
    
    # Add a new column to the matrix
    new_col <- c(13, 14, 15, 16)
    my_matrix <- cbind(my_matrix, new_col)
    print(my_matrix)

Conclusion

This tutorial covered the creation and usage of lists and matrices in R. Lists are versatile and can store mixed data types, while matrices are ideal for numeric or character data in a two-dimensional format.




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