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workflow-builder-collections.md

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Collections

The following operations can be applied when working with Collections. By Collections we refer to any variable that it is an array or an object implementing Traversable

Filter

The filter method removes all the elements that do not satisfy the given predicate (boolean expression). Upon processing, the Exchange will hold a lazy Collection.

You can specify a PHP callable as a predicate. The callback should accept two arguments: the current item and the current key. In the following example we keep all the numbers less than 50.

$builder
  ->start()
  ->filter(function ($current, $key) {
    return $current < 50;
  })
  ->end();

The above example can rewritten using Simple expressions, as follows:

$builder
  ->start()
  ->filter('current < 25')
  ->end();

First

The first method keeps only the first element of the collection. Upon processing the Exchange will hold a single element (not a Collection).

No configuration is required for first method.

$builder
  ->start()
  ->first()
  ->end();

Last

Similar to first, the last method keeps only the last element of the collection. Upon processing the Exchange will hold a single element (not a Collection).

No configuration is required for last method.

$builder
  ->start()
  ->last()
  ->end();

Find

The find method keeps only the first element that satisfies the predicate. Upon processing, the Exchange will hold a single element (not a Collection).

You can specify a PHP callable as a predicate. The callback should accept two arguments: the current item and the current key. In the following example we keep all the numbers less than 50.

$builder
  ->start()
  ->find(function ($current, $key) {
    return $current < 50;
  })
  ->end();

The above example can rewritten using Simple expressions, as follows:

$builder
  ->start()
  ->find('current < 25')
  ->end();

Sort

The sort method sorts the collection according to the provided expression (compare function). Upon processing, the Exchange will hold a non-lazy Collection.

You can specify a PHP callable as a predicate. The callback should accept two arguments: the current item and the current key. In the following example we keep all the numbers less than 50.

$builder
  ->start()
  ->sort(function ($a, $b) {
    return $a - $b;
  })
  ->end();

The above example can rewritten using Simple expressions, as follows:

$builder
  ->start()
  ->sort('a - b')
  ->end();

Map

The map method iterates through the collection and passed each value to the given callback. The callback must return the new instance of the item, thus creating a new collection of items.

You can specify a PHP callable as a predicate. The callback should accept two arguments: the current item and the current key. In the following example we keep all the numbers less than 50.

$builder
  ->start()
  ->map(function ($current, $key) {
    return $current * 10;
  })
  ->end();

The above example can rewritten using Simple expressions, as follows:

$builder
  ->start()
  ->map('current * 10')
  ->end();