Working with expressions - 7.3

Talend Data Mapper User Guide

Version
7.3
Language
English
Product
Talend Big Data Platform
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Module
Talend Studio
Content
Design and Development > Designing Jobs
Last publication date
2023-01-05

Expressions use functions, arguments and references to map elements in order to define the actions to be performed in the map.

An expression can use three types of elements:
  • Functions: units of code that accept arguments and return a single value.
  • Arguments: parameters used to define a function, a filter for example.
  • Map elements: references to elements in the input or output structure of the map.

In the expression below, SimpleLoop is a function, Input Map Element, Filter, Sort Keys, and Contexts are arguments and /PurchaseOrderShipping/Address is a reference to a map element.

Expressions can be displayed in two formats:
  • As tree nodes, like in the example above, which allows you to edit the expression by dragging an dropping functions and map elements.
  • As text, which allows you to manipulate the expression by typing. The following text represents the same expression as in the image above:
    SimpleLoop(in$/PurchaseOrderShipping/Address,{Filter},{Sort Keys},{Contexts})

Expressions are displayed as trees by default, but you can change this parameter in the preferences. For more information, see General preferences.