> For the complete documentation index, see [llms.txt](https://viewzenlabsug.gitbook.io/userguides/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://viewzenlabsug.gitbook.io/userguides/appverse/apps/create-an-app/forms/create/get-familiar/appverse-expressions.md). # Appverse Expressions ### Current value . (dot) ### Referencing a Form Field * ${} - Returns the value of field enclosed within {} * Example - ${firstname} will return 'John' if John was entered in the firstname field ### Functions #### String Functions * String Functions | Function | Description | Example | | -------------------------------------- | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | | concat(string1, string2, ...) | Joins multiple strings into one. | concat('Name', ' : ', ${firstname}) → "Name : John" | | string-length(string) | Returns the length of a string. | string-length(${firstname}) → 4 (if ${firstname} = "John") | | substr(string, start, length) | Extracts a substring from a string. | substr('hello', 1, 3) → "hel" | | translate(string, from, to) | Replaces characters in a string. | translate('abc', 'a', 'x') → "xbc" | | join(delimiter, string1, string2, ...) | Combines data from multiple fields into a single string. | join(' ', ${first\_name}, ${middle\_name}, ${last\_name}) -> "John M Smith" if John is the first\_name, M is the middle\_name and Smith is the last\_name | * Date and Time Functions | Function | Description | Example | | ------------------------- | ------------------------------------------------------------------ | ----------------------------------------------- | | today() | Returns the current date. | today() → 2025-01-22 | | now() | Returns the current date and time. | now() → 2025-01-22T14:30:00 | | format-date(date, format) | Formats a date into a string. | format-date(today(), '%Y-%m-%d') → "2025-01-22" | | decimal-date-time(date) | Converts a date-time to a decimal number (days since Jan 1, 1970). | decimal-date-time(today()) → 19848.0 | | date(date\_string) | Converts a string into a date object. | date('2025-01-22') → 2025-01-22 | | time(time\_string) | Converts a string into a time object. | time('14:30:00') → 14:30:00 | * Mathematical Functions | Function | Description | Example | | ----------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------- | | abs(number) | Returns the absolute value. | abs(-5) → 5 | | ceil(number`)` | Rounds a number up to the nearest integer. | ceil(4.2) → 5 | | floor(number`)` | Rounds a number down to the nearest integer. | floor(4.9) → 4 | | round(number, decimals) | Rounds a number to a specific decimal place. | round(4.567, 2) → 4.57 | | int(number) | Converts a number to an integer. | int(4.9) → 4 | | pow(base, exponent) | Raises a number to a power. | pow(2, 3) → 8 | | mod(number, divisor) | Returns the remainder of a division. | mod(10, 3) → 1 | | sum(repeat-group) | Sums a set of values in the repeat group field or list of numbers | sum(${receivableamount}) $receivableamount is a field in a repeat group | | avg(repeat-group) | Calculates the average of a set of values in the repeat group field or list of numbers | avg(${receivableamount}) $receivableamount is a field in a repeat group | | count(repeat-group) | Counts the number of instances of a repeat group | sum(${rptgrpmembers}) $rptgrpmembers is a repeat group in the form | | min(repeat-group) | Min of the values of a repeat group field | min(${receivableamount}) $receivableamount is a field in a repeat group | | max(repeat-group) | Max of the values of a repeat group field | max(${receivableamount}) $receivableamount is a field in a repeat group | | sum-if( | Sums a set of values in the repeat group field or list of numbers based on a condition | sum-if (${receivableamount}, ${receivableamount} > 1000) $receivableamount is a field in a repeat group | * Logical Functions | Function | Description | Example | | ---------------------------------------- | -------------------------------------------------------------------- | --------------------------------- | | if(condition, true\_value, false\_value) | Returns one value if the condition is true, otherwise another value. | if(${age} > 18, 'Adult', 'Minor') | | coalesce(value1, value2, ...) | Returns the first non-empty value. | coalesce(${name}, 'Unknown') | * Comparison and Boolean operators | Function | Description | Example | | ---------------------------------- | ----------------------------------------------- | --------------------------------------------- | | boolean(value) | Converts a value to boolean (true/false). | boolean(1) → true | | not(expressio`n)` | Returns the opposite boolean value. | not(${consent\_given}) | | and(expression1, expression2, ...) | Returns true if all conditions are true. | and(${age} > 18, ${consent} = 'yes') | | or(expression1, expression2, ...) | Returns true if at least one condition is true. | or(${age} > 18, ${guardian\_consent} = 'yes') | * Instance Functions | Function | Description | Example | | ----------------------------------- | -------------------------------------------------------------- | ----------------------------------------------- | | count(node-set) | Counts the number of repeated group instances. | count(/data/repeat\_group) | | position() | Returns the index of the current repeat group instance. | position() = 1 (first instance) | | indexed-repeat(field, group, index) | Retrieves a field value from a specific repeat group instance. | indexed-repeat(${name}, /data/repeat\_group, 2) | * Geographic Functions | Function | Description | Example | | -------------------------------- | ------------------------------------------------------- | -------------------------------------------- | | distance(lat1, lon1, lat2, lon2) | Calculates the distance (in meters) between two points. | distance(${lat1}, ${lon1}, ${lat2}, ${lon2}) | | area(node-set) | Computes the area of a polygon or shape. | area(${polygon}) | * Selection Functions | Function | Description | Example | | ------------------------- | -------------------------------------------------------------------------- | ----------------------------------------------- | | uuid() | Generates a unique identifier. | uuid() → "123e4567-e89b-12d3-a456-426614174000" | | digest(string, algorithm) | Returns a hash of the string using the specified algorithm (e.g., `sha1`). | digest('password', 'sha1') | | jr:choice(field, value) | Used to retrieve the description (label) of the selected list value | jr:choice($gender, 'male') will return Male | | count-selected(list) | Counts the number of selected choices | count-selected(${members}) | | selected(value, list) | Checks if a value is selected in a multi-select question. | selected(${gender}, 'male') | | selected-at(list, index) | Returns the selected item at a given index. | selected-at(${gender}, 1) | ### Common Date Formats | Format String | Example (for 2025-01-22) | Description | | -------------- | -------------------------- | ------------------------- | | '%Y-%m-%d' | 2025-01-22 | Year-Month-Day (ISO 8601) | | '%d-%m-%Y' | 22-01-2025 | Day-Month-Year | | '%m/%d/%Y' | 01/22/2025 | Month/Day/Year | | '%b %d, %Y' | Jan 22, 2025 | Abbreviated month name | | '%B %d, %Y' | January 22, 2025 | Full month name | | '%y-%m-%d' | 25-01-22 | Two-digit year | | '%a, %d %b %Y' | Wed, 22 Jan 2025 | Abbreviated weekday name | | '%A, %d %B %Y' | Wednesday, 22 January 2025 | Full weekday name | #### **Time Formatting** | Format String | Output Example (14:30:45) | Description | | ------------- | ------------------------- | ---------------------------- | | '%H:%M:%S' | 14:30:45 | 24-hour time (HH:MM:SS) | | '%I:%M %p' | 02:30 PM | 12-hour time with AM/PM | | '%H:%M' | 14:30 | 24-hour time without seconds |