Lua in Neovim: Break and Nested Loops — Star Patterns & Finding Divisible Numbers | Episode 11

Lua in Neovim: Break and Nested Loops — Star Patterns & Finding Divisible Numbers

Master loop control in Lua by using break to exit loops early and nested for loops to create star patterns. This example demonstrates building a star rectangle and triangle, plus finding the first number divisible by both 7 and 13, illustrating how break affects only the innermost loop.

Code

-- Star Rectangle: 5 rows, 10 columns
for row = 1, 5 do
  local line = ""
  for col = 1, 10 do
    line = line .. "*"
  end
  print(line)
end

print() -- blank line

-- Star Triangle: rows with increasing stars
for row = 1, 5 do
  local line = ""
  for col = 1, row do
    line = line .. "*"
  end
  print(line)
end

print() -- blank line

-- Find first number divisible by both 7 and 13 between 1 and 200
for num = 1, 200 do
  if num % 7 == 0 and num % 13 == 0 then
    print("First number divisible by 7 and 13 is:", num)
    break  -- exits this loop immediately
  end
end

Key Points

• break immediately exits the current (innermost) loop when executed.
• Nested loops run one loop inside another, with each loop having its own independent counter.
• Star patterns can be created by controlling the number of iterations in nested loops.
• Using break inside nested loops only stops the innermost loop, not outer loops.
• Nested loops are useful for building grids, tables, and searching through combinations efficiently.