# Advanced Filters To add an advanced matches filter, select "matches (advanced)" from the filter's drop-down menu. In the text field, enter your filter expression.

#### Filter Expressions Filter expressions in ChainArgos are not case-sensitive. To enter a special character in a "matches (advanced)" filter, first add a leading carat `^`. For example, to filter on `hamas, terrorist`, you would enter `hamas ^, terrorist`.

Example Filter Expression	Description
`foo`	is equal to "`foo`" exactly (not case-sensitive)
`foo ^, bar`	is equal to either `foo` or `bar`, exactly
`%foo%`	contains "foo" in any part of the result, matches with "buffoon" and "fast food"
`foo%`	starts with "foo", matches "foolish" and "food" but not "buffoon" or "fast food"
`%foo`	ends with "foo", matches "buffoo" and "fast foo" but not "buffoon" or "fast food"
`f%od`	starts with an "f" and ends with "od", matches "fast food"
`EMPTY`	string is empty (has no characters) or is null (no value)
`NULL`	value is null
`-foo`	is not equal to "foo" (is any value except "foo"), matches "pizza", "trash", "fun" but not "foo"
`-foo ^, -bar`	is not equal to either "foo" or "bar", but matches any value except "foo" and "bar"
`-%foo%`	doesn't contain "foo", does not match "buffoon" or "fast food"
`-foo%`	doesn't start with "foo", does not match "foolish" or "food"
`-%foo`	doesn't end with "foo", does not match "buffoo" or "fast foo"
`-EMPTY`	string is not empty (has at least one character)
`-NULL`	value is not null
`foo% ^, bar`	starts with "foo" or is "bar" exactly, matches "food" and matches "bar", but not "barfood"
`foo% ^, -food`	starts with "foo" but is not "food"
`_uf`	has any single character followed by "uf", matches "buffoon"

#### Custom "User Attributes" Your ChainArgos system administrator can configure user-specific values called "user attributes" that let you automatically customize a Look and/or Dashboard for each user (optional). To reference a "user attribute" in an advanced matches filter, use the syntax `{{ _user_attributes['name_of_your_attribute'] }}`. Custom "User Attributes" are a ChainArgos option, please contact ChainArgos to find out more about customizable "user attributes".