Skip to main content

In Expressions

The in operator has been extended to support string searches and table searches. For these purposes, it's the fastest possible solution.

Searching for a substring.
assert("world" in "hello world")

When used on tables, the in operator searches for values. It'll search for array elements and it'll search keys for their values.

Searching a table for a value.
local t = { "a", "b", key = "value" }

assert("a" in t) -- "a" is an element inside of t.
assert("b" in t) -- "b" is an element inside of t.
assert("value" in t) -- "value" is the value of a key inside of t.
assert(not "random" in t) -- "random" is not an element OR the value of a key inside of t.

Rules​

  • The right-hand operand must always be a table or a string.
  • The left-hand operand must be a string if the right-hand operand is a string.
  • The left-hand operand can be anything if the right-hand operand is a table.
caution

The bytecode of this feature is not backwards-compatible with Lua.