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error 404 matchChunk | revDocs | RunRev
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Product Edition
Version
matchChunk
Basics
Expander triangle
Type
Function
Syntax
matchChunk(string,regularExpression[,positionVarsList])
See Also
Introduced
1.0
Changed
2.0
Environment
Desktop, Web and Server
Platform Support
MacOS,Mac OS X,Windows,Linux
Security
None required
Summary
Returns true if a regular expression is found in the specified string, false otherwise.
Examples

matchChunk("Hello","Hel") -- returns true
matchChunk("Hello","o$") -- also returns true
matchChunk(the short name of this stack,"^rev") -- starts with "rev"
matchChunk(field "Title",myExpr,startMatch,endMatch)

Additional Comments
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Use the matchChunk function to check whether a string contains a specified pattern.

Parameters:

The string is any expression that evaluates to a string.

The regularExpression is any expression that evaluates to a regular expression.

The optional positionVarsList consists of an even number of existing variables, separated by commas.

Value:

The matchChunk function returns true or false.

Comments:

If the regularExpression includes a pair of parentheses, the position of the substring matching the part of the regular expression inside the parentheses is placed in the variables in the positionVarsList. The number of the first character in the matching substring is placed in the first variable in the positionVarsList, and the number of the last character is placed in the second variable. Additional starting and ending positions, matching additional parenthetical expressions, are placed in additional pairs of variables in the positionVarsList. If the matchChunk function returns false, the values of the variables in the positionVarsList are not changed.

The string and regularExpression are always case-sensitive, regardless of the setting of the caseSensitive property. (If you need to make a case-insensitive comparison, use "(?i)" at the start of the regularExpression to make the match case-insensitive.)

Important! Variables in the positionVarsList must be created before the matchChunkfunction is called. The matchChunkfunction, unlike the putcommand, does not create them automatically.

The matchChunk and matchText functions return the same value, given the same string and regularExpression. The difference between the two is that the matchChunk function records the positions of matched substrings in the optional positionVarsList variables, while the matchText function records the substrings themselves.

Tip: Revolution implements regular expressions compatible with the PCRE library. For detailed information about regular expression elements you can use with this function, see the PCRE manual at <http://www.pcre.org/man.txt>.

Changes to Revolution:

The regular expression format changed in version 2.0 to use PCRE compatible syntax.

User Comments
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