# Operators

## Mathematical operators

operators Name Description
- subtract
* multiply
/ divide
^ exponentiate Raises one number to the power of another, e.g. 2 ^ 2 is 4
% modulus Returns the remainder of a number, e.g. 5 % 2 is 1
MOD modulus Returns the remainder of a number, e.g. 5 mod 2 is 1
\ integer divide Divides giving an integer result, e.g. 7 \ 2 is 3
++ increment Increments a number. Can be used before or after an assignment, e.g. a = b++ would assign the value of b to a, then increment b. a = ++b would increment b, then assign the new value to a. In both cases, b would be incremented. (not thread safe, see below)
-- decrement Decrements a number. Can be used before or after an assignment, e.g. a = b-- would assign the value of b to a, then decrement b. a = --b would decrement b, then assign the new value to a. In both cases, b would be decremented. (not thread safe, see below)
+= Compound add A shorthand operator for adding to a value, e.g. a += b is equivalent to writing a = a + b
-= Compound subtract A shorthand operator for subtracting from a value, e.g. a -= b is equivalent to writing a = a - b
*= Compound multiply A shorthand operator for multiplying a value, e.g. a *= b is equivalent to writing a = a * b
/= Compound divide A shorthand operator for dividing a value, e.g. a /= b is equivalent to writing a = a / b

### Demonstration of unsafe threaded behavior with ++ and -- operators

```echo(server.lucee.version & "<br>");
s = getTickCount();
cycles = 2000;
echo("cycles: " & cycles &" <br>");
function test(){
var array = [];
for ( var x = 1; x lte cycles; x++ ) {
array.append( x );
}
var ops = {
plusPlus: 0,
minusMinus: 0
};
array.each( ( el ) => {
ops.plusPlus++;
ops.minusMinus--;
dump( var=ops, label="values should always be 2000 or -2000, but these operators aren't thread safe");
}
function testSafe(){
var array = [];
for ( var x = 1; x lte cycles; x++ ) {
array.append( x );
}
var ops = {
plusPlus: 0,
minusMinus: 0
};
array.each( ( el ) => {
lock name="loop" type="exclusive" {
ops.plusPlus++;
ops.minusMinus--;
}
dump( var=ops, label="values will always be 2000 or -2000, due to locking");
}
test();
}
testSafe();
}
//}
echo ("<br>" & (getTickCount()-s) & "ms");
```

## Logical operators

operators Name Description
! logical inversion ! true is false
NOT logical inversion not true is false
AND logical and Returns true if both operands are true, e.g. 1 eq 1 and 2 eq 2 is true
&& logical and Returns true if both operands are true, e.g. 1 eq 1 && 2 eq 2 is true
OR logical or Returns true if either or both operands are true, e.g. 1 eq 1 or 2 eq 3 is true
|| logical or Returns true if either or both operand are true, e.g. 1 == 1 || 2 == 3 is true
XOR logical exclusive or Returns true if either operand is true, but not both, e.g. 1 == 1 XOR 2 == 3 is true, but 1 == 1 XOR 2 == 2 is false

## Comparison operators

operators Name Description
EQ equals Returns true if operands are equal, e.g. "A" EQ "A" is true
== equals Returns true if operands are equal, e.g. "A" == "A" is true
=== identical Returns true if operands are the same object in memory, false if they are not, (Note this is different than how JavaScript's === operator works.
NEQ does not equal Returns true if operands are not equal, e.g. "A" NEQ "B" is true
<> does not equal Returns true if operands are not equal, e.g. "A" <> "B" is true
!= does not equal Returns true if operands are not equal, e.g. "A" != "B" is true
!== is not identical Returns true if operands are not equal or not of the same type, e.g. 1 !== "1" is true, but 1 !== 1 is false
GT greater than Returns true if the operand on the left is has a higher value than the operand on the right, e.g. 1 GT 2 is false
> greater than Returns true if the operand on the left is has a higher value than the operand on the right, e.g. 1 > 2 is false
LT less than Returns true if the operand on the left has a lower value than the operand on the right, e.g. 1 LT 2 is true
< less than Returns true if the operand on the left has a lower value than the operand on the right, e.g. 1 < 2 is true
GTE greater than or equal to Returns true if the operand on the left has a value higher than or equal to the operand on the right, e.g. 2 GTE 2 is true
>= greater than or equal to Returns true if the operand on the left has a value higher than or equal to the operand on the right, e.g. 2 >= 2 is true
LTE less than or equal to Returns true if the operand on the left has a value lower than or equal to the operand on the right, e.g. 2 LTE 2 is true
<= less than or equal to Returns true if the operand on the left has a value lower than or equal to the operand on the right, e.g. 2 <= 2 is true
CONTAINS contains Returns true if the left operand contains the right operand, e.g. "SMILES" CONTAINS "MILE" is true
CT contains Returns true if the left operand contains the right operand, e.g. "SMILES" CT "MILE" is true
DOES NOT CONTAIN does not contain Returns true if the left operand does not contain the right operand, e.g. "SMILES" DOES NOT CONTAIN "RHUBARB" is true
NCT does not contain Returns true if the left operand does not contain the right operand, e.g. "SMILES" NCT "RHUBARB" is true

## String operators

operators Name Description
& concatenation Joins two strings, e.g. The result of "Hello" & "World" is "HelloWorld"
&= compound concatenation A shorthand operator that joins two strings, e.g. a &= b would be equivalent to writing a = a & b

## Ternary operator

The ternary operator lets you return results conditionally, in a very compact amount of code:

```condition ? value1 : value2
```

This would return value1 if condition is true, otherwise it would return false. It's comparable to the following logical structure:

```<cfif condition>
#value1#
<cfelse>
#value2#
</cfif>
```

or the function:

```iif(condition, "value1", "value2")
```

For example:

animal = "cat"; writeOutput(animal == "cat"? "Meow" : "Woof");

would output "Meow".

## Elvis operator

The "Elvis operator" in Lucee works like a Null Coalescing operator in other languages. If the expression to the left of the operator refers to a variable that does not exist, or is null, then the expression on the right is then evaluated and is the result of the full expression. If the expression to the left of the operator refers to a variable that does exist, the right hand expression is never evaluated.

Some examples:

```// the variable 'rockstar' does not exist, so
// "Elvis Presley" is the result of the expression
dump( var=rockstar ?: "Elvis Presley", label="rockstar ?: ""Elvis Presley""" );
// another example of variable does
// not exist - this time showing
// that the right hand side is evaluatd
i=1;
dump( var=( n ?: ++i ), label="n ?: ++i" );
dump( var=i, label="i (expect to be changed from 1 to 2)" );
// an example of the variable DOES
// exist - proving that the right
// hand side is NOT evaluatd
i=1;
n=2;
dump( var=( n ?: ++i ), label="n ?: ++i" );
dump( var=i, label="i (expect to be 1, still unchanged)" );
// the variable is declared but is null
// right hand is chosen
rockstar=NullValue();
dump( var=( rockstar ?: "Joni Mitchell" ), label="rockstar ?: ""Joni Mitchell""" );
// it can be used with complex variables
complexVar = [ { test=[ { test=2 } ] } ];
dump( var=( complexVar[ 2 ].test[ 1 ].test ?: "Default" ), label="complexVar[ 2 ].test[ 1 ].test ?: ""Default""" )
dump( var=( complexVar[ 1 ].test[ 1 ].test ?: "Default" ), label="complexVar[ 1 ].test[ 1 ].test ?: ""Default""" )
// Finally, this is not a shorthand of the
// ternary operator. The variable EXISTS
// its boolean value is not relevant to elvis
someVar=false;
dump( var=( someVar ?: true ), label="someVar ?: true" );
```

## Operators not available in tags

You can use <> > < >= and <= in tags, as long as they don't interfere with the tag syntax. In that case you must use the equivalent GT, LT, etc. operators instead.

## Casting

Note that in Lucee values are cast to an appropriate type automatically, except when using the identical operators === and !==

For example:

```<cfset a = "2">
<cfset b = a ^ 2>
```

returns 4. It casts the string to a number as it needs to.