PHP面试题之驼峰字符串转换成下划线样式例子

$str = 'OpenAPI';

$length = mb_strlen($str);

$new = '';

for($i = 0; $i < $length; $i++)
{
 $num = ord($str[$i]);
 $pre = ord($str[$i - 1]);

 $new .= ($i != 0 && ($num >= 65 && $num <= 90) && ($pre >= 97 && $pre <= 122)) ? "_{$str[$i]}" : $str[$i];
} www.111com.net

echo strtolower($new) . '
';

echo strtolower(preg_replace('/((?<=[a-z])(?=[A-Z]))/', '_', $str)).'
';

f = new File("d:/temp/t.txt")
if(f.exists()){
    f.eachLine{ line->
        line = line.trim()
        String[] elems = line.split('_')
        for(int i = 0; i < elems.length; i++){
            elems[i] = elems[i].toLowerCase()
            if(i != 0){
                String elem = elems[i]
                char first = elem[0] as char
                elems[i] = "" + (char)(first - 32) + elem.substring(1)
            }
        }
        println elems.join()
    }
}