Iterator | Documentation

The Iterator component is a generic component that allows users to iterate over an array of data.

#Release Stage

Alpha

#Configuration

To configure an Iterator, you need to specify three pieces of information

Name	Key	Type	Description
Input (required)	`input`	string	The data you want to iterate over
Components (required)	`component`	array[object]	Array of components
Output Elements (required)	`output-elements`	object	Output of the iterator

#Input

The input data is what you want to iterate over. For example, if a variable is text-array with the format array:strint, you can configure the iterator with input: ${variable.text-array}.

#Range

In addition to using input to iterate over all elements in an array, users can also specify a range. The range consists of three values: start, stop, and an optional step.

There are two representations for the range setting:

#Array Representation

range: [0, 5, 2]
---
range: 
  - 0
  - 5
  - 2

#Map Representation

range: 
  start: 0 
  stop: 5
  step: 2

You can also use reference syntax within the range. For example:

range: 
  start: 0 
  stop: ${variable.top-k}
  step: 2

#Component

The component dictionary mirrors the structure of the component dictionary in the pipeline recipe. You can include multiple components inside the Iterator. The key difference is that components within the Iterator can use the element of the Iterator as input, by referencing ${iterator.element}.

#Output Elements

The output-elements is a map of string-to-string. It specifies the output of the Iterator, and the Iterator will concatenate the results into an array. For example, in the following recipe, the Iterator collects the ${base64.output.data} from each iteration and merges them into an array.

#Example Recipe

variable:
  text-array:
    title: Text Array
    type: array:string
output:
  result-0:
    title: Result 0
    value: ${iterator-0.output.result}
  result-1:
    title: Result 1
    value: ${iterator-1.output.result}
component:
  iterator-0:
    type: iterator
    input: ${variable.text-array}
    component:
      base64-encode-0:
        type: base64
        task: TASK_ENCODE
        input:
          data: ${iterator-0.element}
    output-elements:
      result: ${base64-encode-0.output.data}
  iterator-1:
    type: iterator
    range: [0,2]
    component:
      base64-encode-1:
        type: base64
        task: TASK_ENCODE
        input:
          data: ${variable.text-array[i]}
    output-elements:
      result: ${base64-encode-1.output.data}