search a php array for partial string match

There are several ways...

$arr = array(0 => 'blue', 1 => 'red', 2 => 'green string', 3 => 'red');

Search the array with a loop:

$results = array();

foreach ($arr as $value) {

  if (strpos($value, 'green') !== false) { $results[] = $value; }

}

if( empty($results) ) { echo 'No matches found.'; }
else { echo "'green' was found in: " . implode('; ', $results); }

Use array_filter():

$results = array_filter($arr, function($value) {
    return strpos($value, 'green') !== false;
});

In order to use Closures with other arguments there is the use-keyword. So you can abstract it and wrap it into a function:

function find_string_in_array ($arr, $string) {

    return array_filter($arr, function($value) use ($string) {
        return strpos($value, $string) !== false;
    });

}

$results = find_string_in_array ($arr, 'green');

if( empty($results) ) { echo 'No matches found.'; }
else { echo "'green' was found in: " . implode('; ', $results); }

Here's a working example: http://codepad.viper-7.com/xZtnN7

You can use preg_grep function of php. It's supported in PHP >= 4.0.5.

$array = array(0 => 'blue', 1 => 'red', 2 => 'green string', 3 => 'red');
$m_array = preg_grep('/^green\s.*/', $array);

$m_array contains matched elements of array.

PHP 5.3+

array_walk($arr, function($item, $key) {
    if(strpos($item, 'green') !== false) {
        echo 'Found in: ' . $item . ', with key: ' . $key;
    }
});

For a partial match you can iterate the array and use a string search function like strpos().

function array_search_partial($arr, $keyword) {
    foreach($arr as $index => $string) {
        if (strpos($string, $keyword) !== FALSE)
            return $index;
    }
}

For an exact match, use in_array()

in_array('green', $arr)