Logic Apps (Standard) Data Mapper supports complex structural transformations between records and fields in source and destination schemas. Functions perform calculations by using predefined formulas and specific values called arguments (or inputs). The mapper executes these calculations in a defined order based on records and fields.
To use a function, select it from the Function panel and add it to the mapping area. Next, link the function to nodes in the source and destination schemas. This approach lets you transform data as it flows from the source message to the target message.
For example, you can concatenate values, add DateTime information, or apply other transformations. Consider the following examples:
- The Add function sums two or more numeric values.
- The Concat function combines multiple strings into a single value.
- The Count function returns the number of items in a collection.
Note: All functions rely on XPath 3.0 (at least at the time of writing).
Data Mapper groups functions into categories based on their purpose. For instance, string functions handle tasks such as trimming and concatenation. Likewise, mathematical functions perform numeric operations. In the Data Mapper, functions appear on demand, organized by category in the Function panel.
📝 One-Minute Brief
Functions play a key role in message transformations. This article explains what a function is in the Logic Apps Standard Data Mapper, how functions work with arguments, and how they help transform data between source and destination schemas.
Function Categories and Description
The following table lists the function categories, briefly describes each, and shows the functions in each category, including links to their corresponding reference pages.
| Function category Category description | Functions in category |
| Collection Used to perform a variety of operations over collections, such as cumulative sum, short, or get distinct values. | Average, Count, Direct Access, Distinct Values, Filter, Index, Join, Maximum, Minimum, Reverse, Sort, Sub Sequence, Sum |
| Conversion Used to convert values to specific times. | To DateTime, To integer, To number, To string |
| Date and Time Used to perform a variety of operations over Dates, such as retrieving the current date and time or adding dates. | Add days, Add DayTime to Date, Add DayTime to DateTime, Add DayTime to Time, Add YearMonth to DateTime, Adjust Date, Adjust DateTime, Adjust Time, Current date. Current DateTime value, Current time, DateTime, Day from DAte, Day from DateTime, Equal Date, Equal DateTime, Equal Day, Equal Month, Equal MonthDay, Equal Time, Equal Year, Equal YearMonth, Greater Date, Greater DateTime, Greater Time, Hours from DateTime, Hours from Time, Less Date, Less DateTime, Less Time, Minutes from DateTime, Minutes from Time, Month from Date, Month from DateTime, Seconds from DateTime, Seconds from Time, Subtract Dates, Subtract DateTimes, Subtract DateTime from Date, Subtract DateTime from DateTime, Subtract DateTime from Time, Subtract Times, Subtract YearMonth from Date, Subtract YearMonth from DateTime, Time zone from Date, Time zone from DateTime, Time zone from Time, Year from Date, Year from DateTime. |
| Logical comparison Used to perform a variety of logical operations, such as greater than and logical existence. | Equal, Exists, Greater, Greater or equal, if, if else, Is date, Is DateTime, Is nil, Is null, Is number, Is string, Less, Less or equal, Logical AND, Logical NOT, Logical OR, Not equal |
| Mathematical Used to perform a variety of mathematical and scientific operations, such as addition and multiplication. | Utility Used to perform a variety of additional and distinct operations that don’t fit in the above Categories, such as stopping a transformation and returning the specified error code and description, or formatting a number or a date. |
| String Used to perform a variety of string functions, such as trimming and concatenation. | Codepoints to string, Concat, Contains, Ends with, Length, Lowercase, Name, Regular expression matches, Regular expression replace, Replace, Start with, String to codepoints, Substring, Substring after, Substring before, Trim, Trim left, Trim right, Uppercase |
| Utility Used to perform a variety of additional and distinct operations that don’t fit in the above Categories, such as stopping a transformation and returning the specified error code and description or format a number or a date. | Copy, Error, Format date, Format DateTime value, Format number, Format time |
Note: The purpose of a function is usually obvious from its name.
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