
154
Chapter 7: Using Regular Expressions in Functions
For example, the following statement replaces the uppercase string "HELLO" with a lowercase
"hello". This example uses backreferences to perform the replacement. For more information on
using backreferences, see
“Using backreferences in replacement strings” on page 153
.
reReplace("HELLO", "([[:upper:]]*)", "Don't shout\scream \L\1")
The result of this example is the string "Don't shout\scream hello".
Escaping special characters in replacement strings
You use the backslash character, \, to escape backreference and case-conversion characters in
replacement strings. For example, to include a literal "\u" in a replacement string, escape it, as in
"\\u".
Omitting subexpressions from backreferences
By default, a set of parentheses will both group the subexpression and capture its matched text for
later referral by backreferences. However, if you insert "?:" as the first characters of the
subexpression, ColdFusion performs all operations on the subexpression except that it will not
capture the corresponding text for use with a back reference.
This is useful when alternating over subexpressions containing differing numbers of groups would
complicate backreference numbering. For example, consider an expression to insert a "Mr." in
between Bonjour|Hi|Hello and Bond, using a nested group for alternating between Hi & Hello:
<cfset regex = "(Bonjour|H(?:i|ello))( Bond)">
<cfset replaceString = "\1 Mr.\2">
<cfset string = "Hello Bond">
#reReplace(string, regex, replaceString)#
This example returns "Hello Mr. Bond". If you did not prohibit the capturing of the Hi/Hello
group, the \2 backreference would end up referring to that group instead of " Bond", and the
result would be "Hello Mr.ello".
Returning matched subexpressions
The
REFind
and
REFindNoCase
functions return the location in the search string of the first
match of the regular expression. Even though the search string in the next example contains two
matches of the regular expression, the function only returns the index of the first:
<cfset IndexOfOccurrence=REFind("
BIG
", "Some BIG BIG string")>
<!--- The value of IndexOfOccurrence is 5 --->
To find all instances of the regular expression, you must call the
REFind
and
REFindNoCase
functions multiple times.
Both the
REFind
and
REFindNoCase
functions take an optional third parameter that specifies the
starting index in the search string for the search. By default, the starting location is index 1, the
beginning of the string.
To find the second instance of the regular expression in this example, you call
REFind
with a
starting index of 8:
<cfset IndexOfOccurrence=REFind("
BIG
", "Some BIG BIG string", 8)>
<!--- The value of IndexOfOccurrence is 9 --->
In this case, the function returns an index of 9, the starting index of the second string " BIG ".
Содержание ColdFusion MX
Страница 1: ...Developing ColdFusion MX Applications...
Страница 22: ...22 Contents...
Страница 38: ......
Страница 52: ...52 Chapter 2 Elements of CFML...
Страница 162: ......
Страница 218: ...218 Chapter 10 Writing and Calling User Defined Functions...
Страница 250: ...250 Chapter 11 Building and Using ColdFusion Components...
Страница 264: ...264 Chapter 12 Building Custom CFXAPI Tags...
Страница 266: ......
Страница 314: ...314 Chapter 14 Handling Errors...
Страница 344: ...344 Chapter 15 Using Persistent Data and Locking...
Страница 349: ...About user security 349...
Страница 357: ...Security scenarios 357...
Страница 370: ...370 Chapter 16 Securing Applications...
Страница 388: ...388 Chapter 17 Developing Globalized Applications...
Страница 408: ...408 Chapter 18 Debugging and Troubleshooting Applications...
Страница 410: ......
Страница 426: ...426 Chapter 19 Introduction to Databases and SQL...
Страница 476: ...476 Chapter 22 Using Query of Queries...
Страница 534: ...534 Chapter 24 Building a Search Interface...
Страница 556: ...556 Chapter 25 Using Verity Search Expressions...
Страница 558: ......
Страница 582: ...582 Chapter 26 Retrieving and Formatting Data...
Страница 668: ......
Страница 734: ...734 Chapter 32 Using Web Services...
Страница 760: ...760 Chapter 33 Integrating J2EE and Java Elements in CFML Applications...
Страница 786: ...786 Chapter 34 Integrating COM and CORBA Objects in CFML Applications...
Страница 788: ......
Страница 806: ...806 Chapter 35 Sending and Receiving E Mail...