Symbols

Question 1

~

Answer 1

The ~ is used to separate the dependent variable (response variable) from the independent variables (predictors) in formulas for statistical models like:

lm(), glm(), and others

Question 2

Uses for $ symbol

$ - Accessing Columns in a Data Frame

Answer 2

A data frame is essentially a list of columns, and you can use $ to access a specific column by its name.

Access the ‘age’ column
data$age
# Output: 25 30 35

Question 3

Uses for $ symbol

$ - Accessing Elements in a List

Answer 3

You can use $ to extract an element from a list by its name.

Access the ‘scores’ element
my_list$scores
# Output: 90 85 95

Question 4

Uses for $ symbol

$ - Assigning Values

Answer 4

You can use $ to assign values to elements in a data frame or a list

my_list$new_element <- “New Value” # Add a new element to the list

Question 5

Uses for $ symbol

$ - Using $ with Functions

Answer 5

$ can also be used in combination with functions to access specific elements of objects returned by those functions

model <- lm(mpg ~ wt, data = mtcars)
model$coefficients # Access the coefficients of the model

Question 6

()

Answer 6

for grouping and invoking functions

Question 7

[]

Answer 7

used for indexing or subsetting data structures