Page 174 - Beginning PHP 5.3

Part II: Learning the Language
However, an element with the same numeric key doesn ’ t get overwritten; instead the new element is
added to the end of the array and given a new index:
$authors = array( “Steinbeck”, “Kafka”, “Tolkien”, “Dickens” );
$authors = array_merge( $authors, array( 0 = > “Milton” ) );

// Displays “Array ( [0] = > Steinbeck [1] = > Kafka [2] = > Tolkien [3] = >

Dickens [4] = > Milton )”
print_r ( $authors );

If you want to merge arrays while preserving numeric keys, try the array_replace() function (new to
PHP 5.3). For details see http://www.php.net/manual/en/function.array-replace.php.
You can also use array_merge() to reindex a single numerically indexed array, simply by passing the
array. This is useful if you want to ensure that all the elements of an indexed array are consecutively
indexed:

$authors = array( 34 = > “Steinbeck”, 12 = > “Kafka”, 65 = > “Tolkien”, 47 = >

“Dickens” );

// Displays “Array ( [0] = > Steinbeck [1] = > Kafka [2] = > Tolkien [3] = >
Dickens )”

print_r( array_merge( $authors ) );

Converting Between Arrays and Strings
PHP provides a few functions that let you convert a string to an array, or an array to a string.

To convert a string to an array, you can use PHP ’ s handy explode() string function. This function takes
a string, splits it into separate chunks based on a specified delimiter string, and returns an array
containing the chunks. Here ’ s an example:
$fruitString = “apple,pear,banana,strawberry,peach”;

$fruitArray = explode( “,”, $fruitString );

After running this code, $fruitArray contains an array with five string elements: “ apple , “ pear ,
”
”
“ banana , “ strawberry , and “ peach .
”
”
”
You can limit the number of elements in the returned array with a third parameter, in which case the last
array element contains the whole rest of the string:
$fruitString = “apple,pear,banana,strawberry,peach”;
$fruitArray = explode( “,”, $fruitString, 3 );

In this example, $fruitArray contains the elements “ apple , “ pear , and
”
”
“ banana,strawberry,peach .
”
Alternatively, specify a negative third parameter to exclude that many components at the end of the
string from the array. For example, using – in the example just shown creates an array containing just
3
“ apple ” and “ pear . (The three components “ banana , “ strawberry , and “ peach ” are ignored.)
”
”
”
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