applywhen

applywhen is a concept used in certain programming and scripting contexts, particularly within data processing and configuration systems, to define conditional execution of operations. It specifies that an action or transformation should only be applied when a particular condition is met. This condition is typically evaluated based on the state or content of the data being processed.

The primary purpose of applywhen is to introduce flexibility and control over how data is manipulated. Instead of applying a transformation universally, applywhen allows it to be selectively applied. This is useful in scenarios where different data records or elements might require different processing steps. For example, in a data cleaning pipeline, a specific formatting rule might only need to be applied to records that contain a certain type of error or have a particular field value.

The implementation of applywhen varies depending on the system or language. It often involves a conditional statement, such as an if-then structure, where the "if" part represents the condition and the "then" part represents the action to be taken. The condition can range from simple checks, like comparing a value to a constant, to more complex logic involving multiple fields or external data sources. By using applywhen, developers can create more sophisticated and efficient data processing workflows that adapt to varying data characteristics.