PHP数组合并加上单引号

1.

$str = join(",",$array);
$inStr = "'".str_replace(",","','",$str)."'";

2.

$projectcode_array = ["20130719","20130718","20130717"];

function change_to_quotes($str) {
    return sprintf("'%s'", $str);
 }
$new_projectcode_array =  implode(',', array_map('change_to_quotes', $projectcode_array ));
$new_projectcode_array="'20130719','20130718','20130717'";