Expressions
are the building blocks of the CFML language. In its most basic form,
an expression is nothing more than a single element such as
`1`

, `test`

,
`MyVar`

, or `Chr(54)`

. Compound
expressions let you to evaluate data that is acted upon by operators.
For example, `1*10`

is a mathematical expression
that evaluates to `10`

. The values
`1`

and `10`

are both data, while
the asterisk (`*`

) is considered an operator. On the
other end of the spectrum, expressions can be complex, consisting of
one or more subexpressions:

<cfset x = 1+(10 mod (3 * (11 - acos(-1))))>

Operators allow
you to perform calculations and make comparisons between expressions.
In other words, they allow you to combine simple expressions to form
ones that are more complex. For example, ```
<cfset x =
10*(3+2)>
```

uses the asterisk (`*`

) as an
operator to multiply 10 by the sum of another expression that uses
the plus (`+`

) operator to add 3 and 2. There are
four types of operators available in ColdFusion:

- Arithmetic
Performs arithmetic operations such as sign changes, addition, subtraction, etc., on numeric values.

- Comparison
Compares two values and returns a Boolean

`true`

/`false`

.- String
There is only one string operator in the CFML language. The ampersand (

`&`

) concatenates strings.- Boolean
Also known as logical operators, Boolean operators perform connective and negation operations and return Boolean

`true`

/`false`

values.

Table 2-2 lists the operators available in ColdFusion by order of precedence (P).

Table 2-2. ColdFusion ...

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