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Operators

jameskilford edited this page Jul 24, 2013 · 19 revisions
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Mathematical operators

+ add
- subtract
/ divide
* multiply
^ 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.
-- 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.
+= 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

Logical operators

! 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 == 1 && 2 == 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

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 equal in value, and are of the same type, e.g. 1 === "1" is false, but 1 === 1 is true
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

& 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" is a shortening of the ternary operator. One instance of where this is handy is for returning a 'sensible default' value if an variable does not exist. A simple example might look like this:

    writeOutput(rockstar?: "Elvis Presley");

Outputs the value of "rockstar" if the variable exists, otherwise it outputs "Elvis Presley"

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 Railo 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.

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