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Operators

In this lesson we'll review all the logical operators that are available to use in Lua.  Operators are special expessions that can be used to determine the relationship of two values.  They are often used in "if" statements to execute code when a condition is met.

Equals


The equals operator is denoted by two equals signs in a row:
==

The equals operator is a test to see if two values are equal.  This does not assign a value to a variable.

n=2
if n==2 then
        print("n equals 2")
end

The equals operator can be used with any data type, including strings and boolean values.

name="Fred"
if name=="Fred" then
        print("The name's Fred")
end

Less Than


The less than operator determines if one number is smaller than another.  The less than sign looks a little bit like a bird's beak if you picture the bird facing to the left:
<

Remember, birds don't eat a lot, so the number where his beak points is smaller.  Here's an example of it in action:

a = 1
if a < 2 then
	print("a is less than 2")
end

Greater Than


The greater than operator determines if one number is larger than another.  The greater than sign looks a little bit like an alligator's mouth if you picture the alligator facing to the left:
>

Remember, alligators eat a lot, so the number where his mouth points is bigger.  Here's an example of it in action:

a = 1
if a > 0 then
        print("a is greater than 0")
end

Less Than or Equal To


This is a variation of the less than operator that will also be true if the values are equal. It is denoted by a less than sign followed by a single equals sign:
<=

Here is an example of its usage:

a = 1
if a <= 1 then
        print("a is less than or equal to 1")
end

Greater Than or Equal To


This is a variation of the greater than operator that will also be true if the values are equal.   It is denoted by a greater than sign followed by a single equals sign:
>=

Here is an example of its usage:

a = 1
if a >= 1 then
        print("a is greater than or equal to 1")
end

Not Equal


This operator is the opposite of the equals operator.  It is indicated by a tilde character followed by a single equals sign:
~=

Here is an example of its usage:

a = 1
if a ~= 5 then
        print("a does not equal 5")
end

Conclusion


You will frequently encounter all of these operators while writing Lua scripts.  Make sure you understand how they all work, and ask on the forum if you have any questions.  You're doing great!