#Foreach php how to#

The essence of the Iterator Pattern is to 'Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.'. See also the UML class and sequence diagram below. New access and traversal operations can be defined independently by defining new iterators. For example, if you need to have the elements presented.

Clients use an iterator to access and traverse an aggregate without knowing its representation (data structures).ĭifferent iterators can be used to access and traverse an aggregate in different ways. For an array, foreach presents the elements of the array in the order that they were added to the array.

The foreach( ) loop gives you the value of each array element, but the for( ) loop gives.

Define a separate (iterator) object that encapsulates accessing and traversing an aggregate object. With for( ), you get the position explicitly in your loop variable.

What solution does the Iterator design pattern describe?

Later without having to change the aggregate interface. New traversal operations should be defined for an aggregate object without changing its interface.ĭefining access and traversal operations in the aggregate interface is inflexible because it commits the aggregate to particular access and traversal operations and makes it impossible to add new operations.The elements of an aggregate object should be accessed and traversed without exposing its representation (data structures).What problems can the Iterator design pattern solve?

#Foreach php how to#

That describe how to solve recurring design problems to design flexible and reusable object-oriented software, that is, objects that are easier to implement, change, test, and reuse. Design pattern is one of the twenty-three well-known