# Operators Just as a sentence means nothing without a verb, anything you write in [RuLa](/rule-language/what-is-the-rule-language.md) means nothing without operators. They make it possible for a variable to be defined, for a condition to work and for a rule to make sense. The table below lists all available operators in alphabetical order, with a brief description. For a more extensive description of each individual operator, plus examples, click on it or visit the sub-pages in the menu on the left. ### Available Operators and Keywords | Operator | Description | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`=`](/rule-language/operators/boolean-operators/equal.md), [`!=`](/rule-language/operators/boolean-operators/not-equal.md), [`<`](/rule-language/operators/boolean-operators/less-than.md), [`<=`](/rule-language/operators/boolean-operators/less-than-or-equal.md), [`>`](/rule-language/operators/boolean-operators/greater-than.md), [`>=`](/rule-language/operators/boolean-operators/greater-than-or-equal.md) | Perform basic comparisons. Evaluate to either true or false. | | [`:=`](/rule-language/operators/special-operators/assign.md) | Assignment, which can have any kind of expression on the right side of the operator. | | [`+`](/rule-language/operators/mathematical-operators/+.md), [`-`](/rule-language/operators/mathematical-operators/+.md), [`/`](/rule-language/operators/mathematical-operators/+.md), [`*`](/rule-language/operators/mathematical-operators/+.md), [`%`](/rule-language/operators/mathematical-operators/+.md) | Perform basic mathematical calculations. | | [`[]`](/rule-language/operators/list-operators/list.md) | Creates a new list from single values, allowing other list operators to perform actions on the new list. | | [`[]`](/rule-language/operators/list-operators/access.md) | Accesses an element of a list by its zero-based index. | | [`{}`](/rule-language/operators/dictionary-operators/create.md) | Creates a new dictionary from key-value pairs, allowing other dictionary operators to perform actions on the new dictionary. | | [`ADD_DAYS`](/rule-language/operators/date-operators/add_days.md) | Takes a date and adds a specified number of days to it. | | [`ADD_MONTHS`](/rule-language/operators/date-operators/add_months.md) | Takes a date and adds a specified number of months to it. | | [`ADD_WEEKDAYS`](/rule-language/operators/date-operators/add_weekdays.md) | Takes a date and adds a specified number of weekdays (Mon–Fri), skipping weekends. | | [`ADD_YEARS`](/rule-language/operators/date-operators/add_years-3.md) | Takes a date and adds a specified number of years to it. | | [`AFTER`](/rule-language/operators/date-operators/after.md) | Takes two dates, and checks if the first one comes after the second one. | | [`AFTER_EQUAL`](/rule-language/operators/date-operators/after_equal.md) | Takes two dates, and checks if the first one comes after, or is the same as, the second one. | | [`ALL`](/rule-language/operators/list-operators/all.md) | Evaluates if all values in a list are true. | | [`APPEND`](/rule-language/operators/list-operators/append.md) | Returns a new list with a single element appended to the end. Does not mutate the original. | | [`and`](/rule-language/operators/boolean-operators/and.md) | Sets as condition that both expressions have to be true to have the entire expression evaluate to 'true'. | | [`and then`](/rule-language/operators/boolean-operators/and-then.md) | Similar as above, but when using 'and then', the second question is only asked when the first evaluates to 'true'. | | [`ANY`](/rule-language/operators/list-operators/any.md) | Evaluates if at least one value in a list is true. Alias for `SOME`. | | [`AVG`](/rule-language/operators/mathematical-operators/avg.md) | Calculates the average value. | | [`AVG_OF_ANY`](/rule-language/operators/unknown-operators/avg_of_any.md) | Calculates the average of available values. | | [`BEFORE`](/rule-language/operators/date-operators/before.md) | Takes two dates, and checks if the first one comes before the second one. | | [`BEFORE_EQUAL`](/rule-language/operators/date-operators/before_equal.md) | Takes two dates, and checks if the first one comes before, or is the same as, the second one. | | [`calculated_name`](/rule-language/operators/string-operators/calculated_name.md) | Accesses the calculated name of an instance. | | [`CEIL`](/rule-language/operators/mathematical-operators/ceil.md) | Returns the value of the given parameter, rounded up to a whole number. | | [`CLAMP`](/rule-language/operators/mathematical-operators/clamp.md) | Clamps a numeric value between a minimum and maximum. | | [`COMB`](/rule-language/operators/mathematical-operators/comb.md) | Returns the number of ways to choose k items from n items (n choose k). | | [`CONCAT`](/rule-language/operators/string-operators/concat.md) | Combines two values into one new value, specifying what should separate the two. | | [`CONCAT_OF_ANY`](/rule-language/operators/unknown-operators/concat_of_any.md) | Like `CONCAT`, but only combines the values that are available (not unknown). | | [`contains`](/rule-language/operators/list-operators/contains.md) | Goes over a list, which is given on the left of the operator. Evaluates to 'true' if the single value on the right is present in the given list. | | [`contains all`](/rule-language/operators/list-operators/contains-only.md) | Expressions with this operator will only evaluate to 'true' if all values from the list on the right side are present in the list on the left side. | | [`contains any`](/rule-language/operators/list-operators/contains-any.md) | Going over a list, given on the left side of the operator, this operator has the expression evaluate to true if any value from that list is present in a list or the single value given on the right side. | | [`COUNT`](/rule-language/operators/list-operators/count.md) | Returns the length of a list, dictionary, or string. Alias for `LEN`. | | [`CUSTOM_MAX`](/rule-language/operators/list-operators/custom_max.md) | Returns the maximum element in a list as ranked by a second ordering list. | | [`DATE_EQUAL`](/rule-language/operators/date-operators/date_equal.md) | Returns true if two dates refer to the same calendar date, ignoring time. | | [`DATETIME_EQUAL`](/rule-language/operators/date-operators/datetime_equal.md) | Returns true if two datetime values refer to the exact same point in time. | | [`DAYS_AGO`](/rule-language/operators/date-operators/days_ago.md) | Returns the number of days since a given date. | | [`DAYS_BETWEEN`](/rule-language/operators/date-operators/days_between.md) | Returns the number of days between two dates. | | [`DAYS_SPENT_IN_STATE`](/rule-language/operators/date-operators/days_spent_in_state.md) | Returns the number of days the current case has spent in a given state. | | [`ENDS_WITH`](/rule-language/operators/string-operators/ends_with.md) | Returns true if a string ends with the given suffix. | | [`ensure`](/rule-language/operators/special-operators/ensure.md) | Makes sure a case contains at least, for example, 1 Person. (replaces `create`) | | [`filter()`](/rule-language/operators/list-operators/filter.md) | Applies a conditional expression to a list, keeping only elements where the condition is true. | | [`FILTER`](/rule-language/operators/list-operators/filter-1.md) | Removes all occurrences of a specified value from a list. | | [`FILTER_FALSE`](/rule-language/operators/list-operators/filter_false.md) | Removes all `false` elements from the provided arguments. | | [`FILTER_UNKNOWN`](/rule-language/operators/list-operators/filter_unknown.md) | Removes all `unknown` values from a list. | | [`FIRST_ELEMENT`](/rule-language/operators/list-operators/first_element.md) | Returns the first element from a list. | | [`FLATTEN`](/rule-language/operators/list-operators/flatten.md) | Extracts values from a list of dictionaries by key, or concatenates a list of lists into a single list. | | [`FLOOR`](/rule-language/operators/mathematical-operators/floor.md) | Returns the value of the given parameter, rounded down to a whole number. | | [`FORMAT_DATE`](/rule-language/operators/date-operators/format_date.md) | Formats a date as a human-readable string using a format pattern. | | [`FORMAT_DATETIME`](/rule-language/operators/date-operators/format_datetime.md) | Formats a datetime value as a human-readable string using a format pattern. | | [`format`](/rule-language/operators/string-operators/format.md) | Takes a string template and replaces named placeholders with provided values. | | [`get_attr`](/rule-language/operators/special-operators/get_attr.md) | Gives access to named properties of an instance using expressions. | | [`GET_TRANSLATED_ATTR`](/rule-language/operators/special-operators/get_translated_attr.md) | Like `get_attr`, but returns the translated display value of the attribute. | | [`get_properties`](/rule-language/operators/special-operators/get-properties-from-instances.md) | Returns specific information on an instance's properties. | | [`has_attr`](/rule-language/operators/special-operators/has_attr.md) | Returns true if an instance has a given attribute defined. | | [`HOURS_BETWEEN`](/rule-language/operators/date-operators/hours_between.md) | Returns the number of hours between two datetime values. | | [`HOURS_SPENT_IN_STATE`](/rule-language/operators/date-operators/hours_spent_in_state.md) | Returns the number of hours the current case has spent in a given state. | | [`in`](/rule-language/operators/list-operators/in.md) | Checks if a value is present in a taxonomy. | | [`INDEX_OF`](/rule-language/operators/list-operators/index_of.md) | Returns the index of the first occurrence of a value in a list or string. Returns -1 if not found. | | [`instances`](/rule-language/operators/special-operators/instances.md) | Returns all instances of the given type(s) living on the platform. | | [`instances_exist`](/rule-language/operators/special-operators/instances_exist.md) | Returns true if the case has at least one instance of the specified type(s). | | [`IS_DATE`](/rule-language/operators/date-operators/is_date.md) | Returns true if the given value can be parsed as a valid date or datetime. | | [`IS_WEEKDAY`](/rule-language/operators/date-operators/is_weekday.md) | Returns true if the date falls on a Monday through Friday. | | [`IS_WEEKEND`](/rule-language/operators/date-operators/is_weekend.md) | Returns true if the date falls on a Saturday or Sunday. | | [`is`](/rule-language/operators/special-operators/is.md) | Basic assignment of a variable. | | [`IS_UNIQUE_NAME`](/rule-language/operators/special-operators/is_unique_name.md) | Returns true if no active instance of the given type with that name exists. | | [`JOIN`](/rule-language/operators/string-operators/join.md) | Combines a list of values into one new value by appending them. | | [`JOIN_OF_ANY`](/rule-language/operators/unknown-operators/join_of_any.md) | Like `JOIN`, but only joins the values that are available (not unknown). | | [`known`](/rule-language/operators/unknown-operators.md) | Sets a condition for when a property is not unknown. | | [`LAST_ELEMENT`](/rule-language/operators/list-operators/last_element.md) | Returns the last element from a list. | | [`LEFT`](/rule-language/operators/string-operators/left.md) | Returns the first n characters (or elements) from a string or list. | | [`LEN`](/rule-language/operators/string-operators/len.md) | Returns the length of a string, list, or dictionary. Alias for `COUNT`. | | [`LEVENSHTEIN`](/rule-language/operators/string-operators/levenshtein.md) | Returns the number of single-character edits needed to transform one string into another. | | [`LIST_OF_ANY`](/rule-language/operators/unknown-operators/list_of_any.md) | Builds a list of only the values that are available out of all the values it is given. | | [`LOWER`](/rule-language/operators/string-operators/lower.md) | Converts a string to lowercase. | | [`MAKE_FILENAME`](/rule-language/operators/string-operators/make_filename.md) | Converts a string into a safe filename. | | [`map()`](/rule-language/operators/list-operators/map.md) | Performs the same action on each individual value in a list using method syntax. | | [`MAP`](/rule-language/operators/list-operators/map-1.md) | Performs the same action on each individual value in a list. | | [`MARKDOWN_TABLE`](/rule-language/operators/string-operators/markdown_table.md) | Renders a list of dictionaries as a Markdown table. | | [`matches` (`=~`)](/rule-language/operators/boolean-operators/matches.md) | Checks if a string matches a regular expression. | | [`MAX`](/rule-language/operators/mathematical-operators/max.md) | Returns the highest value. | | [`MAX_OF_ANY`](/rule-language/operators/unknown-operators/max_of_any.md) | Returns the highest out of available values. | | [`MIN`](/rule-language/operators/mathematical-operators/min.md) | Returns the lowest value. | | [`MIN_OF_ANY`](/rule-language/operators/unknown-operators/min_of_any.md) | Returns the lowest out of available values. | | [`MONTHS_AGO`](/rule-language/operators/date-operators/months_ago.md) | Returns the number of months since a given date. | | [`NAME_AND_LOG`](/rule-language/operators/special-operators/name_and_log.md) | Evaluates an expression, logs its result under a name for debugging, and returns the result unchanged. | | [`not`](/rule-language/operators/boolean-operators/not.md) | A negation. | | [`not in`](/rule-language/operators/list-operators/not-in.md) | Evaluates to true if the given value is absent from the specified taxonomy. | | [`NOW`](/rule-language/operators/date-operators/now.md) | Current date and time. | | [`ontology`](/rule-language/operators/special-operators/ontology.md) | Sets a condition based on the type of ontology. | | [`or`](/rule-language/operators/boolean-operators/or.md) | When just one of the two given expressions is true, the entire expression evaluates to 'true'. | | [`or else`](/rule-language/operators/boolean-operators/or-else.md) | Similar to above, but the second question is only asked if the first has been answered. | | [`PAD_LEFT`](/rule-language/operators/string-operators/pad_left.md) | Pads a string on the left to the given width. Default fill is a space. | | [`PAD_RIGHT`](/rule-language/operators/string-operators/pad_right.md) | Pads a string on the right to the given width. Default fill is a space. | | [`PICK_OR_DEFAULT`](/rule-language/operators/special-operators/pick_or_default.md) | Returns a value from an allowed list if it matches the input, otherwise returns a default. | | [`PRETTY_PRINT`](/rule-language/operators/special-operators/pretty_print.md) | Formats a dictionary or list as an indented, human-readable JSON string. | | [`QUARTER_OF`](/rule-language/operators/date-operators/quarter_of.md) | Returns the quarter (1–4) of the year for a given date. | | [`REPLACE`](/rule-language/operators/string-operators/replace.md) | Replaces all occurrences of a value in a string with another value. | | [`REPLACE_CHARS`](/rule-language/operators/string-operators/replace_chars.md) | Replaces characters in a string one-for-one using two equal-length character sequences. | | [`REVERSE`](/rule-language/operators/list-operators/reverse.md) | Reverses the order of elements in a list. | | [`RIGHT`](/rule-language/operators/string-operators/right.md) | Returns the last n characters (or elements) from a string or list. | | [`roles`](/rule-language/operators/special-operators/roles.md) | Sets a condition based on role(s). | | [`ROUND`](/rule-language/operators/mathematical-operators/round.md) | Returns the value of the given parameter, rounded to a whole number. | | [`self`](/rule-language/operators/special-operators/self.md) | Refers to the current [instance](/guides/glossary/instance.md) where you use it. | | [`SET`](/rule-language/operators/list-operators/set.md) | Removes duplicates from a list. | | [`SET_DIFFERENCE`](/rule-language/operators/list-operators/set_difference.md) | Returns the elements in the first set that are not in the second set. | | [`INTERSECTION`](/rule-language/operators/list-operators/intersection.md) | Returns the elements that appear in both lists. | | [`SLICE`](/rule-language/operators/string-operators/slice.md) | Returns a portion of a string or list between a start and end index. | | [`SNEAKY`](/rule-language/operators/unknown-operators/sneaky.md) | Wrapping an expression with `SNEAKY` has the system ignore the expression, if the information used in it is not available. | | [`SOME`](/rule-language/operators/list-operators/some.md) | Evaluates if any value in a list is true. | | [`SORT`](/rule-language/operators/list-operators/sort.md) | Sorts a list. | | [`SPLIT`](/rule-language/operators/string-operators/split.md) | Splits a string by a separator into a list. Optional max splits. | | [`SQRT`](/rule-language/operators/mathematical-operators/sqrt.md) | Returns the square root of a number. | | [`STARTS_WITH`](/rule-language/operators/string-operators/starts_with.md) | Returns true if a string starts with the given prefix. | | [`STRING_TO_JSON`](/rule-language/operators/string-operators/string_to_json.md) | Parses a JSON-encoded string and returns the corresponding dictionary or list. | | [`SUBTRACT_YEARS`](/rule-language/operators/date-operators/subtract_years.md) | Takes a date and subtracts a specified number of years from it. | | [`SUM`](/rule-language/operators/mathematical-operators/sum.md) | Adds up numbers. | | [`SUM_OF_ANY`](/rule-language/operators/unknown-operators/sum_of_any.md) | Adds available numbers. | | [`SUM_PRODUCT`](/rule-language/operators/mathematical-operators/sum_product.md) | Multiplies values in one list with values on the same index in another list. Returns the sum of the multiplications. | | [`TODAY`](/rule-language/operators/date-operators/today.md) | The current date. | | [`Translate (.$)`](/rule-language/operators/special-operators/translate.md) | Accesses a taxonomy attribute in a way that its value is translated into the requested language at render time. | | [`TRANSLATE_STRING`](/rule-language/operators/string-operators/translate_string.md) | Returns a translation marker for a custom string key, resolved at render time. | | [`TRIM`](/rule-language/operators/string-operators/trim.md) | Removes whitespace (or specified characters) from the beginning and end of a string. | | [`TRIM_LEFT`](/rule-language/operators/string-operators/trim_left.md) | Removes whitespace (or specified characters) from the beginning of a string. | | [`UNION`](/rule-language/operators/list-operators/union.md) | Combines the elements of two sets into one single set. | | [`UNION_OF_ANY`](/rule-language/operators/unknown-operators/union_of_any.md) | Creates a combined list of the available values and lists out of all values and lists you provide. | | [`unknown`](/rule-language/operators/unknown-operators/unknown.md) | Sets a condition for when a property is unknown. | | [`UPPER`](/rule-language/operators/string-operators/upper.md) | Converts a string to uppercase. | | [`UUID`](/rule-language/operators/string-operators/uuid.md) | Generates a random UUID string. | | [`WEEKDAYS`](/rule-language/operators/date-operators/weekdays.md) | Returns the number of weekdays (Mon–Fri) between two dates. | | [`YEARS_AGO`](/rule-language/operators/date-operators/years-ago.md) | Calculates the number of years since a given date. | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.atfinity.io/rule-language/operators.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.