PHP , Search and Replace array element inside string

i try to search and replace array element inside string but don't know how to do this ! my code ex :

function check_strings($string_text){

    $string_text = 'some random text with random lenght '; //random text with randon lenght 
    $array_of_3000 = ['some','text','hello','no','why','oh','random']; // array with lenght of 3000
    $text_tokens = explode($string_text,' ');
    foreach($text_tokens as$token_index =>$token ){
        if (in_array($token, $array_of_3000)){
            // replce $token with new_token => <a href='site_url('/$token')'>  $token </a>  on $string_text
            //update $string_text
        }
    }
    return $string_text;
}

how can i do it ? thanks for your helps :)