Description

Inserts an element at the beginning of a list.

Returns

A copy of the list, with value inserted at the first position.

Category

List functions

Function syntax

ListPrepend(list, value [, delimiters, includeEmptyFields ])

History

ColdFusion (2018 release) Update 5:

  • Introduced named parameters.
  • New parameter added- includeEmptyFields.

See also

ListAppendListInsertAtListSetAtLists in Data types- Developing guide in the Developing ColdFusion Applications

Parameters

Parameter

Description

list

A list or a variable that contains one.

value

An element or a list of elements.

delimiters

A string or a variable that contains one. Characters that separate list elements. The default value is comma. If this parameter contains more than one character, ColdFusion only uses the first character and ignores the others.

includeEmptyFields Boolean to determine to include empty fields from the list that is prepended to the list.

Usage

When prepending an element to a list, ColdFusion inserts a delimiter. If delimiters_ contains more_ than one delimiter character, ColdFusion uses the first delimiter in the string; if delimiters is omitted, ColdFusion uses a comma.ColdFusion ignores empty list elements; thus, the list "a,b,c,,,d" has four elements.If the delimiters parameter is the empty string (""), ColdFusion returns the contents of the value parameter.

Example 1

<cfscript>
       myList="Tokyo,Bangkok,Jakarta,Manila,Bangalore,Shanghai";
       myAppend=ListPrepend(myList,"Singapore");
       WriteOutput(myAppend); // Inserts Singapore at the beginning of the list
</cfscript>

Output

Singapore,Tokyo,Bangkok,Jakarta,Manila,Bangalore,Shanghai

Example 2

When includeEmptyFields="true"

<cfscript>
	mylist="John,Paul,George"
	writeOutput(ListPrepend(list=mylist,value=",,,Ringo,,",delimiter=",",includeEmptyFields="true"))
</cfscript>

Output

,,,Ringo,,,John,Paul,George

<cfscript>
	mylist="Paul,George"
	writeOutput(ListPrepend(list=mylist,value=",,John,,,Ringo,,",delimiter=",",includeEmptyFields="true"))
</cfscript>

Output

,,John,,,Ringo,,,Paul,George

When includeEmptyFields="false"

<cfscript>
	mylist="John,Paul,George"
	writeOutput(ListPrepend(list=mylist,value=",,,Ringo,,",delimiter=",",includeEmptyFields="false"))
</cfscript>

Output

Ringo,John,Paul,George

<cfscript>
	mylist="Paul,George"
	writeOutput(ListPrepend(list=mylist,value=",,John,,,Ringo,,",delimiter=",",includeEmptyFields="false"))
</cfscript>

Output

Ringo,John,Paul,George

Member function

<cfscript>
	mylist="Paul,George"
	writeOutput(mylist.ListPrepend(",,John,,,Ringo,,",",","false"))
</cfscript>

Output

John,Ringo,Paul,George