Specifications

For example, the following code

$array = array(4, 5, 1, 2, 3, 1, 2, 1);

$ac = array_count_values($array);

creates an array called $ac that contains

Key Value

This indicates that 4, 5, and 3 occurred once in $array, 1 occurred three times, and 2 occurred

twice.

Converting Arrays to Scalar Variables: extract()

If we have an associative array with a number of key value pairs, we can turn them into a set

of scalar variables using the function extract(). The prototype for extract() is as follows:

extract(array var_array [, int extract_type] [, string prefix] );

The purpose of extract() is to take an array and create scalar variables with the names of the

keys in the array. The values of these variables are set to the values in the array.

Here is a simple example.

$array = array( “key1” => “value1”, “key2” => “value2”, “key3” => “value3”);

extract($array);

echo “$key1 $key2 $key3”;

This code produces the following output:

value1 value2 value3

The array had three elements with keys: key1, key2, and key3. Using extract(), we created

three scalar variables, $key1, $key2, and $key3. You can see from the output that the values of

$key1, $key2, and $key3 are “value1”, “value2”, and “value3”, respectively. These values

came from the original array.

There are two optional parameters to extract(): extract_type and prefix. The variable

extract_type tells extract() how to handle collisions. These are cases in which a variable

already exists with the same name as a key. The default response is to overwrite the existing

variable. Four allowable values for extract_type are shown in Table 3.1.

Using Arrays

HAPTER 3

USING ARRAYS

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