Question

This is how it can be done, in several lines:

// $str represents string that needs cleaning:
$str = " String with   line\nbreak and too  much spaces   ";
// Clean string with preg_replace():
$str = preg_replace('/[\x00-\x09\x0B-\x1F\x7F]|^ +| +$/', '', $str);
$str = preg_replace('/\x0A| +/', ' ', $str);

echo $str;
// Output:
"String with line break and too much spaces"

My quoestion focuses in combining two preg_replace() lines into one preg_replace() that does exactly same job.

Is that possible and if it is how it should be done?

---

There is many different uses for that behavior, one that I am after is defining regexp as constant or variable and use that within class function to clean up and validate user input.

Simplified example of suchs class:

class cleaner{
    protected $defined_methods = array(
    'TRIM' => '/ +/',
    'STRIP_CC' => '/[\x00-\x1F\x7F]/',
    'TRIM_STRIP_CC' => array('/[\x00-\x1F\x7F]/', '/ +/')
    );
    protected $defined_results = array(
    'TRIM' => ' ', 
    'STRIP_CC' => '',
    'TRIM_STRIP_CC' => array('', ' ')
    );

    function clean(array $input, array $methods){
        foreach ($input as $key => $data){
            $input[$key] = preg_replace($defined_methods[$methods[$key]], $defined_results[$methods[$key]], $data);
        }
        return $input;
    }
}

This way validation method (regexp) can vary with input data if needed so.

Answer 1

$str = preg_replace(
    $patterns = array('/[\x00-\x09\x0B-\x1F\x7F]|^ +| +$/', '/\x0A| +/'),
    $replace  = array('',                                   ' '), 
    $str
);

See preg_replace, it supports multiple replacements after each other.