ListPrepend |
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Description
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Inserts an element at the beginning of a list.
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Returns
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A copy of the list, with value inserted at the first position.
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Category
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List functions
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Function syntax |
ListPrepend(list, value [, delimiters ])
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See also
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ListAppend, ListInsertAt, ListSetAt
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Parameters
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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. Character(s) that separate list elements. |
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Default: comma. |
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If this parameter contains more than one character, ColdFusion ony uses the first |
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character and ignores the others. |
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Usage
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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.
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ColdFusion ignores empty list elements; thus, the list "a,b,c,,,d" has four elements.
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If the delimiters parameter is the empty string (""), ColdFusion returns the contents of the value parameter.
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To add an element to the beginning or end of a list, Macromedia recommends that you do so with code such as the following, rather than with the ListAppend or ListPrepend functions:
<cfset MyValue = "another element">
<cfif listLen(myList) is 0>
<cfset myList = MyValue>
<cfelse>
<cfset myList = myList & ", " & MyValue>
</cfif>
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Example<!--- This example shows ListPrepend --->
<cfquery name = "GetParkInfo" datasource = "cfsnippets">
SELECT PARKNAME,CITY,STATE
FROM PARKS
WHERE PARKNAME LIKE `DE%'
</cfquery>
<cfset temp = ValueList(GetParkInfo.ParkName)>
<cfset first_element = ListFirst(temp)>
<cfoutput><p>The original list: #temp#</cfoutput>
<!--- now, insert an element at position 1--->
<cfset temp2 = ListPrepend(Temp, "my Inserted Value")>
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