Values and Formulas

Refer to the following guidelines while using values and formulas to create simple and complex Transformations in Hevo:

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Points to Consider

• Arbitrary expressions can be used. For example, int_col + dec_col * 1000 + STRING_TO_NUMBER(REPLACE(id, "-"," "), 1)

• Constants

  • Everything within “double quotes” is considered a string constant.

  • Integers and decimals are supported

• References

  • Fields from the Events can be specified by using the field names. If a nested field is referenced, each level of nesting must be separated using a .(dot). For example, location.state.name.

  • Identity field may be indicated using $self. This can be used when the field selection is on a condition and several fields may match the condition.

  • A null value may be indicated using the $null keyword.

• Operators may be used to combine the expressions.

• Functions may be used in the expressions.

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Applicable Operators

The following operators are supported:

- +, - , *, /, ==,!=,!

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Applicable Functions

Function Name	Description	Parameters
LOWER	Convert string to lowercase.	Value or formula that returns a string.
UPPER	Convert string to uppercase.	Value or formula that returns a string.
TITLE	Convert string to title case.	Value or formula that returns a string.
SNAKE_CASE	Convert string to snake case.	Value or formula that returns a string.
REPLACE	Find an expression in the given string and replace it with the provided value.	- Regex: “REGEX” if the expression to find is a regular expression, else, “OTHERS”. - Match case: “MATCH_EXACT” if match exact, “OTHERS for case insensitive. - Find: Expression to find. - Replace: Value to replace.
SPLIT_FIELDS	Split a field using a delimiter and create new fields from it.	Delimiter to split on.
SPLIT_ARRAY	Split a field using a delimiter and convert the values into an array.	Delimiter to split on.
JSON_TO_STRING	Convert a JSON object to a string.	Value or formula that returns a JSON object.
PARSE_JSON	Parse a JSON object from a string.	Value or formula that returns a string.
FLATTEN	Flatten a JSON object.	Value or formula that returns a JSON object.
NOW	Returns the current Datetime.	None.
DATE_TO_STRING	Convert a datetime field to a string based on the specified format.	- Value or formula that returns a datetime field. - Output string format.
PARSE_DATE_STRING	Convert a string to a datetime field based on the specified pattern.	- Value or formula that returns a string. - Input string format to identify datetime properties and create the datetime field from.
DATE_ADD	Adds or subtract given time period from a datetime field.	- Value or formula that returns a datetime field. - Datetime unit to modify. - Amount, in number, to be added or subtracted. Use negative value for subtraction.
NUMBER_TO_STRING	Convert a number(integer/decimal) to string based on the given parameter.	- Value or formula that returns a number. Output string pattern can be one of the following: - “PLAIN” - “NUMBER” - “PERCENT” - “SCIENTIFIC” - “CURRENCY” - “Custom pattern”.
STRING_TO_NUMBER	Convert a given string to a number.	Value or formula that returns a string that can be parsed into a number.
ROUND_NUMBER	Round the given decimal value.	- Value or formula that returns a number (integer or decimal). - Rounding Mode * “UP” * “DOWN” * “HALF_UP” * “HALF_DOWN” * “CEILING” * “FLOOR” - Scale: Number specifying the scale. Required if Rounding Mode is one of “UP”, “DOWN”, “HALF_UP”, or “HALF_DOWN”
HASH	Hash a given value or formula using the given strategy.	- Value or formula. - Hash Strategy: * “SHA-256” * “SHA-512” * “MD5”
MASK	Masks the given value or formula.	Value or formula.
RENAME	Renames the given field to a new value.	- Field name or path to the field name to be renamed. - New field name.