String.contains("regex")

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String.contains("regex")

This operator tests whether regex matches the referenced string attribute's value in whole or part. Matches are case-sensitive. Also, but only in an agent context (i.e. in $AgentQuery), case-sensitivity can be overridden by $AgentCaseSensitive. The match gives a Boolean result.

Thus in default settings, String.contains() is always:

• case-insensitive in an agent (as $AgentCaseSensitive is false by default)
• case-sensitive in all other action code contexts

If concerned over unwanted case-sensitivity, use String.icontains() which is always case-insensitive

regex is one of:

• an unquoted action code expression, which includes just referencing a single attribute name e.g. MyString
• a quoted string; quoted strings may be either:
  • a literal string (i.e. actual text)
  • a regular expression.

Important: do not omit the enclosing quotes for literal strings or regex. If omitted, Tinderbox will try to evaluate the string as an expression. Doing this may result in the expected result but this is actually a false positive. So, remember to enclose your regex or literals in quotes.

$MyString.contains("regex") 

For example:

$MyString.contains("regex") 

is true if $MyString matches regex's pattern. Other more complex usage:

$MyString.contains($MyMatchText) 

$MyString.contains($MyString(agent)) 

$MyString(parent).contains("Tuesday") 

"Any day like Saturday is good".contains($MyDay) 

"Any day like Saturday is good".contains("Saturday") 

Note that regex/literal strings are quoted whilst action expressions are not.

Getting the offset of the (first) regex match

If the regular expression regex is found the function returns the match offset+1, where offset is the distance from the start of the string to the start of the matched regex. If there is more than one match, the offset of the first match is returned. Formerly, .contains() returned true if the regex was found. The '+1' modifier ensures that a match at position zero return a number higher than zero which would otherwise coerce to false. Since 1+offset is always true, no changes are required in existing documents but the function also gives usable offset information. Thus, if $MyString is "abcdefgehEi":

$MyNumber = $MyString.contains("e"); returns 5.

$MyNumber = $MyString.contains("E"); returns 10.

$MyNumber = $MyString.contains("eh"); returns 8.

Testing "does not contain"

Use a ! prefix to the query argument:

!$MyString.contains("Tuesday") 

Use of parentheses after the !, around the query, can assist Tinderbox's parsing:

!($MyString.contains("Tuesday")) 

Using back-references

In an agent query or if() conditions the function can return back-references to matches of (sub-)strings.

String.contains() clears the list of back references from previous processes, so $0 and $1 correspond to its own results, not those from prior expressions.

Dealing with inline quote characters

Because regex is parsed for regular expressions, it may be possible to use the '\xNN' form described here to work around the lack of escaping from single double quotes within strings.

Legacy format

This operator the replacement of the older form of AttributeName(regex) which is deprecated and should not be used in new work (legacy support may fall away). Apart from anything else, the current syntax should remove the confusion over whether/when to use the $ prefix with attribute names in queries.