Lists

Chapter 6
Lists, why would you need them?

# Just submit the answer

Lists, why would you need them? (2)

# Just submit the answer to start the first exercise on lists.

Creating a list

# Vector with numerics from 1 up to 10
my_vector <- 1:10 
my_vector
# Matrix with numerics from 1 up to 9
my_matrix <- matrix(1:9, ncol = 3)
my_matrix
# First 10 elements of the built-in data frame mtcars
my_df <- mtcars[1:10,]
my_df
# Construct list with these different elements:
my_list <- list(my_vector, my_matrix,my_df)


Creating a named list

# Vector with numerics from 1 up to 10
my_vector <- 1:10 

# Matrix with numerics from 1 up to 9
my_matrix <- matrix(1:9, ncol = 3)

# First 10 elements of the built-in data frame mtcars
my_df <- mtcars[1:10,]

# Adapt list() call to give the components names
my_list <- list(vec=my_vector, mat=my_matrix, df=my_df)
#Alternative way
#my_list <- list(my_vector, my_matrix, my_df)
#names(my_list) <- c("vec", "mat","df")
# Print out my_list
my_list

Creating a named list (2)

# The variables mov, act and rev are available

# Finish the code to build shining_list
shining_list <- list(moviename = mov, actors=act, reviews=rev)
shining_list

Selecting elements from a list

# shining_list is already pre-loaded in the workspace
shining_list
# Print out the vector representing the actors
shining_list[[2]]

# Print the second element of the vector representing the actors
shining_list[[2]][2]

Creating a new list for another movie

# Use the table from the exercise to define the comments and scores vectors
scores <- c(4.6, 5, 4.8, 5, 4.2)
comments <- c("I would watch it again", "Amazing!", "I liked it", "One of the best movies", 'Fascinating plot') 

# Save the average of the scores vector as avg_review
avg_review=mean(scores)

# Combine scores and comments into the reviews_df data frame
reviews_df=data.frame(scores,comments)

# Create and print out a list, called departed_list
departed_list<- list(movie_title, movie_actors, reviews_df, avg_review)
departed_list