What does tilde by itself mean in Lua?

Question

For the code example:

num_1 = 12 ~ 36

What is the tilde doing in this example? Is it just a shortened way to represent ~= ?

Answer 1

What does tilde by itself mean in Lua?

Operators on their own have no meaning. Only in combination with their operands they make sense.

There are three use-cases for ~ in Lua.

Relational operator ~= unequal: a ~= b is true if a is unequal b

Bitwise operators

1. binary ~ bitwise XOR: a ~ b resolves to a number where every bit is the XORed value of a's and b's respective bit
2. unary ~ bitwise NOT: ~a resolves to a number where every bit is inverted. So zeros become ones and ones become zeros.

In your case num_1 = 12 ~ 36 where ~ is used as a binary operator it is the bitwise XOR.

100100  36
001100  12
------ 
101000  40  

So num_1 = 12 ~ 36 assigns 40 to num_1.

Answer 2

˜ is bitwise exclusive OR. See Bitwise Operators in the Reference Manual.