User Guide

Table Of Contents
Functions 31
Functions
Functions typically manipulate data and return a result. CFML includes over 280 built-in
functions. You can also create user-defined functions (UDFs), sometimes referred to as custom
functions.
Functions have the following general form:
functionName([argument1[, argument2]]...)
Some functions, such as the Now function take no arguments. Other functions require one or
more comma-separated arguments and can have additional optional arguments. All ColdFusion
functions return a value. For example,
Round(3.14159) returns the value 3.
Built-in functions
ColdFusion built-in functions perform a variety of tasks, including, but not limited to, the
following:
Creating and manipulating complex data variables, such as arrays, lists, and structures
Creating and manipulating queries
Creating, analyzing, manipulating, and formatting strings and date and time values
Evaluating the values of dynamic data
Determining the type of a variable value
Converting data between formats
Performing mathematical operations
Getting system information and resources
For alphabetical and categorized lists of ColdFusion functions, see Chapter 3, “ColdFusion
Functions” in CFML Reference.
You use built-in functions throughout ColdFusion pages. Built-in functions are frequently used
in a
cfset or cfoutput tag to prepare data for display or further use. For example, the following
line displays today’s date in the format October 12, 2001:
<cfoutput>#DateFormat(Now(), "mmmm d, yyyy")#</cfoutput>
Note that this code uses two nested functions. The Now function returns a ColdFusion date-time
value representing the current date and time. The
DateFormat function takes the value returned
by the
Now function and converts it to the desired string representation.
Functions are also valuable in CFScript scripts. ColdFusion does not support ColdFusion tags in
CFScript, so you must use functions to access ColdFusion functionality in scripts.