Merging values from different iterators with MultipleIterator

- The MultipleIterator class…merges values from two or more iterators,…but in a fundamentally different way from AppendIterator.…AppendIterator loops through values consecutively…in the order they were appended.…MultipleIterator, on the other hand,…processes values in parallel, generating merged Arrays.…The difference should become clear…with the code in this page, append_multiple.php…which you can find in the Chapter Five folder…of the Exercise Files.…It contains three Arrays of names,…boys, girls, and unisex,…each of which is passed to ArrayIterator,…making it available for chaining with other iterators.…

All three Arrays are appended…to an instance of AppendIterator,…and then a foreach loop displays each value.…Line 16 creates an instance of MultipleIterator,…and the same three Arrays are attached…using the attachIterator method.…Notice that MultipleIterator uses attachIterator,…whereas AppendIterator uses append.…Then, on Lines 23 to 25, a foreach loop…displays the results of MultipleIterator using print_r…