Page 149 - Beginning PHP 5.3

Chapter 6: Arrays

Figure 6-2

Notice how using these functions moves the array pointer forward and backward through the array (the
notable exceptions being current() and key() , which simply return the current value or key without
moving the pointer).

Referring back to the sparse array example in the previous section on the count() function, you now
know how to retrieve the last element of the array without needing to know how it ’ s indexed:

// Create a sparse indexed array
$authors = array( 0 = > “Steinbeck”, 1 = > “Kafka”, 2= > “Tolkien”, 47 = >

“Dickens” );

echo end( $authors ); // Displays “Dickens”
These functions are very useful, but there ’ s a slight problem with them. Each function returns false if an
element couldn ’ t be retrieved. This is all very well, but what if one or more of the elements in your array
actually contain the value false ? In this case, when a function returns false you won ’ t know whether
you ’ re getting back the element ’ s value, or whether there was in fact a problem retrieving the element.

To get round this issue, you can use another PHP function: each() . This returns the current element of
the array, then advances the pointer to the next element. Unlike the previous five functions, however,
each() returns a four - element array rather than a value. This array contains both the key of the current
element, as well as its value. If an element couldn ’ t be retrieved — because the pointer has reached the

end of the array, or because the array is empty — each() returns false . This makes it easy to tell if

each() has retrieved an element with the value of false — in which case it returns the four - element
array — or if it couldn ’ t retrieve an element at all, in which case it returns false .

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