REFind

Returns the position of the first occurrence of a regular expression in a string starting from the specified position. Returns 0 if no occurrences are found. This search is case sensitive.

Returns the position and length of the first occurrence of a regular expression in a string if the returnsubexpressions parameter is set to True. See the description of the returnsubexpressions parameter and the "Usage" section for details.

See also Find, REFindNoCase, and REReplace.

Syntax

REFind(reg_expression, string [, start ] 
    [, returnsubexpressions ] )

reg_expression

Regular expression used for search. This regular expression can include POSIX-specified character classes (for example, [[:alpha:]], [[:digit:]], [[:upper:]], and [[:lower:]]).

string

String being searched.

start

Optional. Starting position for the search. Default is 1.

returnsubexpressions

Optional. A Boolean value indicating whether a substring is returned. If you set this parameter to TRUE, the function returns a CFML structure composed of two arrays containing the position and length of the first substring that matches the criteria of the search. You can retrieve the position and length of the matching subexpression by using the keys "pos" and "len." If there are no occurrences of the regular expression, the "pos" and the "len" arrays each contain one element that has a value of zero. If you set this parameter to FALSE, a scalar value is returned indicating the position of the first occurrence of a regular expression. The default value of this parameter is FALSE.

Usage

In order to find multiple instances of a substring, you must call REFind more than once, each time with a different starting position. To determine the next starting position for the function, use the returnsubexpressions parameter and add the value returned in the position key to the value in the length key.

If you do not use parentheses in the regular expression, the returnsubexpressions parameter returns single element arrays that denote the position and length of the first match found in the string.

If you do use parentheses to denote subexpressions within the regular expression, the returnsubexpressions parameter returns the position and length of the first match of the regular expression in the first element of the respective arrays; the position and length of the first instance of each subexpression within the regular expression are returned in subsequent elements of the arrays.

Examples

<!--- This example shows the use of REFind --->

<HTML>

<HEAD>
<TITLE>
REFind Example
</TITLE>
</HEAD>

<BODY>

<H3>REFind Example</H3>

<P>This example demonstrates the use of the REFind function with and 
without the <i>returnsubexpressions</i> parameter set to True.</P> 

If you do not use the <i>returnsubexpressions</i> parameter, REFind 
returns the position of the first occurrence of a regular expression in a 
string starting from the specified position.  Returns 0 if no occurrences 
are found.
</P>

<P>REFind("a+c+", "abcaaccdd"):    
<CFOUTPUT>#REFind("a+c+", "abcaaccdd")#</CFOUTPUT></P>
<P>REFind("a+c*", "abcaaccdd"):    
<CFOUTPUT>#REFind("a+c*", "abcaaccdd")#</CFOUTPUT></P>
<P>REFind("[[:upper:]]", "abcaacCDD"):    
<CFOUTPUT>#REFind("[[:upper:]]", "abcaacCDD")#</CFOUTPUT></P>
<P>REFind("[\?&]rep=", "report.cfm?rep=1234&u=5"):    
<CFOUTPUT>#REFind("[\?&]rep=", "report.cfm?rep=1234&u=5")#</CFOUTPUT>
</P>
<!--- Set startPos to one; returnMatchedSubexpressions = TRUE --->
<hr size="2" color="#0000A0">

<P>If you do use the <i>returnssubexpression</i> parameter, REFind 
returns the position and length of the first occurrence of a regular 
expression in a string starting from the specified position. The position 
and length variables are stored in a structure. In order to access
the position and length information, you must use the keys <i>pos</i> and 
<i>len</i>, respectively.</P>

<CFSET teststring ="The cat in the hat hat came back!">
<P>The string in which the function is to search is: 
<CFOUTPUT><b>#teststring#</b></CFOUTPUT>.</P>
<P>The first call to REFind to search this string is: <b>REFind("[A-Za-
z]+",testString,1,"TRUE")</b></P>
<P>This function returns a structure that contains two arrays: pos and 
len.</P>
<P>In order to create this structure you can use a CFSET statement, for 
example: </P>
&lt;CFSET st = REFind("[[:alpha:]]",testString,1,"TRUE")&gt;
<CFSET st = REFind("[[:alpha:]]",testString,1,"TRUE")>
<P>
    <CFOUTPUT>
    The number of elements in each array: #ArrayLen(st.pos)#.
    </CFOUTPUT>
</P>
<P><b>The number of elements in the pos and len arrays will always be one 
if you do not use parentheses in the regular expression.</b></P>
<P>The value of st.pos[1] is: <CFOUTPUT>#st.pos[1]#.</CFOUTPUT></P>
<P>The value of st.len[1] is: <CFOUTPUT>#st.len[1]#.</CFOUTPUT></P>
<P>
    <CFOUTPUT>
    Substring is <b>[#Mid(testString,st.pos[1],st.len[1])#]</B>
    </CFOUTPUT>
</P>

<hr size="2" color="#0000A0">

<P>However, if you use parentheses in the regular expression, you will 
find that the first element contains the position and length of the first 
instance of the whole expression. The position and length of the first 
instance of each parenthesized subexpression within will be included in 
additional array elements.</P>

<P>For example: 
&lt;CFSET st1 = REFind("([[:alpha:]])[ 
]+(\1)",testString,1,"TRUE")&gt;</P>

<CFSET st1 = REFind("([[:alpha:]]+)[ ]+(\1)",testString,1,"TRUE")>

<P>The number of elements in each array is 
<CFOUTPUT>#ArrayLen(st1.pos)#</CFOUTPUT>.</P>

<P>First whole expression match; position is <CFOUTPUT>#st1.pos[1]#; 
length is #st1.len[1]#; whole expression match is 
<B>[#Mid(testString,st1.pos[1],st1.len[1])#]</B></CFOUTPUT></P>

<P>Subsequent elements of the arrays provide the position and length of 
the first instance of each parenthesized subexpression therein.</P>
 <CFLOOP index="i" from="2" to="#ArrayLen(st1.pos)#">
    <P><CFOUTPUT>Position is #st1.pos[i]#; Length is #st1.len[i]#; 
Substring is <B>[#Mid(testString,st1.pos[i],st1.len[i])#]</B></
CFOUTPUT></P>
</CFLOOP><BR>   

</BODY>
</HTML>

CFML Language Reference
Chapter 2 : ColdFusion Functions