Learn Lua in Neovim: Logical Operators — and, or, not & Ternary Idiom | Episode 8

Learn Lua Logical Operators: and, or, not & Ternary Idiom

Logical operators in Lua let you combine and manipulate boolean conditions effectively. In this example, we create a theme park ride eligibility checker using and, or, and not operators, plus the common Lua ternary idiom for inline conditional values.

Code

-- Define rider's age and height
local age = 12
local height = 140 -- in centimeters

-- Check if rider meets minimum age and height requirements
local can_ride = (age >= 10) and (height >= 130)

if can_ride then
  print("You can ride!")
else
  print("Sorry, not allowed.")
end

-- Using 'or' to allow entry if either condition is true
local has_ticket = false
local is_vip = true

if has_ticket or is_vip then
  print("Welcome to the park!")
else
  print("Please buy a ticket.")
end

-- Using 'not' to invert a boolean
local park_closed = false

if not park_closed then
  print("The park is open!")
else
  print("The park is closed.")
end

-- Ternary idiom: choose a message based on pass/fail
local score = 75
local result = (score >= 60) and "Pass" or "Fail"
print("Result:", result)

Key Points

• and returns true only if both conditions are true.
• or returns true if at least one condition is true.
• not inverts a boolean value, turning true to false and vice versa.
• The Lua ternary idiom x and a or b selects a if x is true, otherwise b.
• Logical operators enable concise, readable condition checks in Lua scripts.