The rule "Avoid hash optional parameters" is a guideline that encourages developers to explicitly declare parameters instead of using a hash for optional parameters. This is because using a hash for optional parameters can make the code harder to understand and maintain. It can also lead to unexpected behavior if a developer accidentally includes a key in the hash that the method does not expect.

This rule is important because it promotes code readability and maintainability. It also helps prevent potential bugs that may occur due to unexpected keys in the optional hash. By explicitly declaring each parameter, developers can easily see what parameters a method expects, making the code easier to read and understand.

To adhere to this rule, instead of using a hash for optional parameters, explicitly declare each parameter in the method definition. For example, instead of using options = {} in the method definition, declare each parameter like name, email, age. This way, anyone reading the code can easily understand what parameters the method expects and in what order.

The rule "Prefer %i to the literal array syntax" is a guideline that encourages the use of the %i syntax for arrays of symbols. This is a part of the Ruby style guide that aims to promote conciseness and readability.

Symbols are immutable, reusable objects often used in Ruby instead of strings when the value does not need to be changed. When declaring an array of symbols, using the %i syntax can make your code cleaner and easier to read.

To adhere to this rule, instead of declaring an array of symbols using the literal array syntax like [:foo, :bar, :baz], use the %i syntax like %i[foo bar baz]. It's a good practice to consistently use %i for arrays of symbols as it enhances code readability and maintainability.