Boolean Logic

Warmup

• With a partner in pry, use the method below to check the following values: 1.0, “hello”, nil, 0, false, true, “false”

def is_it_truthy(value)
  if value
    "#{value} is truthy!"
  else
    "#{value} is falsey!"
  end
end

• Research: What values are falsey in Ruby?

Truth Tables

• Use a pry session to fill in the table below.

Check Answers

Precedence

Precedence refers to the order of operations which Ruby follows.

!
>, >=, <, <=
><=>, ==, ===, !=, =~, !~
&&
||
=, +=, -=, etc.

Example

false || true && false || false
         \          /
false ||     false     ||  false

             false

Practice

What do you expect the following to return? Why?

false && false || true
false && (false || true)

Complex Practice

For three boolean values (A, B, C), determine the values of the following expressions:

• (A || B) && (A || C)
• (A || !B) || (!A || C)
• ((A && B) && C) || (B && !A)
• ((A && B) && !C) || ((A && C) && !B)

Exercises

See lesson plan.