//1.下劃線命名去除轉(zhuǎn)(explode分割成數(shù)組)
function toUpFirst($str)
    {
        $array = explode('_', $str);
        $result = '';
        $len=count($array);
        if($len>1)
        {
            for($i=0;$i<$len;$i++)
            {
                $result.= ucfirst($array[$i]);
            }
        }
        return $result;
    }
//2.下劃線命名去除轉(zhuǎn)(substr操作字符串)
    function change($str)
    {
        $array = explode('_', $str);
        foreach($array as $key=>$val){
            $newStar = strtoupper(substr($val,0,1));
            $other = substr($val,1);
            $tarr[] = $newStar . $other; 
        }
        return implode("",$tarr);
    }
//駝峰命名轉(zhuǎn)下劃線命名
    function toUnderScore($str)
    {
        $dstr = preg_replace_callback('/([A-Z]+)/',function($matchs)
        {
            return '_'.strtolower($matchs[0]);
        },$str);
        return trim(preg_replace('/_{2,}/','_',$dstr),'_');
    }

下面的是網(wǎng)上大牛寫的，效率高靈巧

/**
* 下劃線轉(zhuǎn)駝峰
* 思路:
* step1.原字符串轉(zhuǎn)小寫,原字符串中的分隔符用空格替換,在字符串開頭加上分隔符
* step2.將字符串中每個單詞的首字母轉(zhuǎn)換為大寫,再去空格,去字符串首部附加的分隔符.
*/
    function camelize($uncamelized_words,$separator='_')
    {
        $uncamelized_words = $separator. str_replace($separator, " ", strtolower($uncamelized_words));
        return ltrim(str_replace(" ", "", ucwords($uncamelized_words)), $separator );
    }

/**
* 駝峰命名轉(zhuǎn)下劃線命名
* 思路:
* 小寫和大寫緊挨一起的地方,加上分隔符,然后全部轉(zhuǎn)小寫
*/
    function uncamelize($camelCaps,$separator='_')
    {
        return strtolower(preg_replace('/([a-z])([A-Z])/', "$1" . $separator . "$2", $camelCaps));
    }