List/Set.icontains("pattern")

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List.icontains("pattern")

This operator tests whether pattern matches the target string attribute or matches a whole discrete value string within a the target list/set attribute value. Matches are always case-insensitive, unlike String/List.contains(). The match gives a Boolean result.

pattern is one of:

• an action code expression (which includes just referencing a single attribute name')
• a quoted literal string (i.e. actual text)

$MyList.icontains("pattern")

The contains operator may also be used with both sets and lists, in which case it tests for set membership, i.e. matching to complete individual values rather than part of values. Thus:

$MyList.icontains("Tuesday") 

is true if $MyList is "Monday;Tuesday;Friday". Other examples:

$MyList.icontains($MyDay) 

$MyList(parent).contains("Tuesday") 

The left-hand argument may also be a literal list:

"Saturday;Sunday".icontains($MyDay) 

From v5.10.2, if the regular expression pattern is found the function now returns the match offset+1, where offset is the distance from the start of the string to the start of the matched pattern. Formerly, .icontains() returned true if the pattern was found. The '+1' modifier ensures that a match at postion 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 now gives usable offset information.

Testing "does not contain"

Use a ! prefix to the query argument:

!$MyList.icontains("Tuesday") 

Dealing with inline quote characters

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