[李景山php] php常见面试题

Php 冒泡排序法 $arr = array('22','2','4','355','1','123','33','55','66','3'); $count = count($arr); for($i=0;$i<$count;$i++){ for($j=0;$j<$count-1;$j++){ if($arr[$j] > $arr[$j+1]){ $temp = $arr[$j+1]; $arr[$j+1] = $arr[$j]; $arr[$j] = $temp; } } } var_dump($arr); 快速排序法 $arr = array('312','322','645','321','22','3','4442'); $arr = quickArr($arr); var_dump($arr); function quickArr($arr=null){ $count = count($arr); if($count <= 1) return $arr; $key = $arr['0']; $arr_left = array(); $arr_right = array(); for($i = 1;$i < $count;$i++){ if($arr[$i] <= $key) $arr_left[] = $arr[$i]; else $arr_right[] = $arr[$i]; } $arr_left = quickArr($arr_left); $arr_right = quickArr($arr_right); return array_merge($arr_left,array($key),$arr_right); } 复杂单表SQL 数据库test有一张user表,字段为id(序号),name(姓名),class(班级),score(分数), 1)写一句SQL,查出全部学生的分数,按降序排序 Select * from user order by score DESC 2)写一句SQL查出每个班的及格人数和不及格人数,格式为:班级 及格人数 不及格人数 select A.class,A.及格人数,B不及格人数 from (select class,clount(*) as 及格人数 from user where score>=60 group by class) as A,(select class,count(*) as 不及格人数 from user where score<60 group by class) as B where A.class=B.class. select A.class,A.及格,B.不及格 from (select class,count(*) as 及格人数 from user where score >= 60 group by class) as A,(select class,count(*) as 不及格人数 from user where score < 60 group by class) as B where A.class=B.class select A.class,A.及格人数,B.不及格人数 from (select class,count(*) as 及格人数 from user where score >=60 group by class) as A,(select class,count(*) as 不及格人数 from user where score<60 group by class ) as B where A.class=B.class. 3)用PHP执行第二小题的SQL,要求判断错误,显示结果,关闭数据库 try{ $dbid = new PDO('mysql:host=localhost;dbname=test','root','098098'); $dbid -> query('SET NAMES UTF8'); }catch(PDOException $e){ die($e->getmessage()); } $stmt = $dbid -> query('select A.class,A.及格,B.不及格 from (select class,count(*) as 及格 from user where score >= 60 group by class) as A,(select class,count(*) as 不及格 from user where score < 60 group by class) as B where A.class=B.class'); if(!$stmt) die('数据库错误'); $result = $stmt -> FETCHALL(PDO::FETCH_ASSOC); if($result){ foreach($result as $val){ echo '班级:'.$val['class'].'及格人数'.$val['及格'].'不及格人数'.$val['不及格'].'<br />'; } }else{ die('执行失败'); } //PDO不需要关闭数据库 非要关可以这样 $dbid = null; 请用正则表达式写一个验证邮箱的PHP程序 $mail = '2-3_2@vip.qq.com'; $pattern = '#^([0-9A-Za-z-_]+@([0-9A-Za-z-\.]+\.([A-Za-z]){2,3}))$#'; $result = preg_match($pattern,$mail); if($result) echo '匹配成功'; else echo '匹配失败'; 以空格作为分隔将字符串 ‘aaa sss ccc eee ww ssq acc’拆分为数组并按字母升序排序,要求所有元素均为小写 $str = 'asd adsds dwew vbfgf reere'; var_dump(arr2sort($str)); function arr2sort($str){ if(empty($str)) return false; $arr = explode(' ',strtolower($str)); if(count($arr) > 1){ sort($arr); return $arr; } return $arr; } 正则匹配一段str只允许大于0的数字和英文逗号,不符合的输入有提示信息 $str = '12033,243,2'; $pattern = '#^([1-9,])+#'; if(preg_match($pattern,$str)) echo '输入正确'; else echo '输入错误'; 将一个数组保存为文件再从文件中读出这个数组 $arr = array('123','sdasd','ewqewq','rewrefv','rwervv','rewrwer'); $arr = file2arr('haha.xxx'); var_dump($arr); function arr2file($arr){ if(is_array($arr)){ $arr = implode(' ',$arr); } return file_put_contents('haha.xxx',$arr); } function file2arr($fileName){ if(!file_exists($fileName)) return false; $str = file_get_contents($fileName); return explode(' ',$str); } $result = arr2file($arr); if($result) echo '写入成功'; else echo '写入失败'; 算出两个文件的相对路径 $a = 'http://www.abc.com/1/2/3/4/5.php'; $b = 'http://www.abc.com/1/2/a/c/vv.php'; $a = parse_url($a); $b = parse_url($b); $aPath = ltrim($a['path'],'/'); $bPath = ltrim($b['path'],'/'); $aArr = explode('/',$aPath); $bArr = explode('/',$bPath); //清除掉两个URL一样的目录 比如/1/2 $countA = count($aArr); for($i = 0; $i<$countA;$i++){ if($aArr[$i] == $bArr[$i]){ unset($aArr[$i]); unset($bArr[$i]); }else{ break; } } //把URL a剩下的目录换成 .. 然后拼接B $countA = count($aArr); for($i = 0;$i<$countA;$i++) $url[] = '..'; $newURL = rtrim(implode('/',$url),'/').'/'.implode('/',$bArr); echo $newURL; 写一个函数能够遍历一个文件夹中所有文件和子文件夹 function showDIR($name){ if(!is_dir($name)) die('这不是一个目录!'); $handle = opendir($name); while($n = readdir($handle)){ if($n == '.' || $n == '..') continue; $fileName = $name.'/'.$n; if(is_dir($fileName)) showDIR($fileName); else echo $fileName.'<br />'; } } 提取出一段URL的文件后缀 $url = 'http://www.abc.com/index.JSP?hh=haha&ye=heihei'; $arr = parse_url($url); $path = explode('.',$arr['path']); echo array_pop($path); 求日期的差数 $date1 = '2012-2-10'; $date2 = '2012-12-21'; $time1 = strtotime($date1); $time2 = strtotime($date2); echo abs($time1-$time2)/(60*60*24); 找出一个数组最大值 $arr = array('11111','22222222','333333333','4444444444444','555555555','4324'); //不让用排序函数就用冒泡或快速排序 rsort($arr); echo $arr['0']; echo max(array('11111','22222222','333333333','4444444444444','555555555','4324')); 读取出<haha></haha>里面的内容,并将<haha>和</haha>替换为<b></b> $str = '<a href="#">adsdasdasd</a><haha>1232rrrrr1312</haha><i>1213213<haha>哦耶</haha>dasdsa</i>'; //取出匹配到的数据 $pattern = '#<haha>(.*?)</haha>#s'; preg_match_all($pattern,$str,$arr); echo '<pre>'; var_dump($arr); echo '</pre>'; //替换匹配到的数据 $pattern2 = '#<(\/)?(haha)>#'; $re = '<${1}b>'; $arr2 = preg_replace($pattern2,$re,$str); echo '<pre>'; var_dump($arr2); echo '</pre>'; 将字符串open_door转换成OpenDoor $str = 'open_door'; $arr = explode('_',$str); foreach($arr as $k => $v) $arr[$k] = ucfirst($v); echo implode('',$arr); 不乱码截取中文字符串 //允许使用mb_substr时 $str = '一二三四五六七'; echo mb_substr($str,3,1,'utf-8'); //不允许使用mb_substr时 function mysub($str,$start,$len='1',$charset='utf-8'){ if($charset=='utf-8') $strlen = 3; else $strlen = 2; $len = $strlen*$len;//得到字符串长度 $start = ($start-1)*$len;//得到截取起点 return substr($str,$start,$len); } echo mysub($str,2,3) 得到访客IP地址,并判断是否属于192.168.90.100 – 192.168.90.150 $ip = $_SERVER['REMOTE_ADDR']; $numIP = str_replace('.','',$ip); if($numIP >= 19216890100 && $numIP <= 19216890150) echo '这个IP在范围内'; echo '不在范围内'; 关联查询asc 有一张表user其中有字段uid和name,另一张表txt里面有字段tid,uid,times,title,contents 要求查询出每个用户的名字以及他一共发表了多少篇文章 try{ $dbid = new PDO('mysql:host=localhost;dbname=haha','root','098098'); $dbid -> query('SET NAMES UTF8'); }catch(PDOException $e){ die($e -> getMessage()); } $stmt = $dbid->query('select A.name,B.postall from (select uid,name from user ) as A,(select uid,count(*) as postall from txt group by uid) as B where B.uid=A.uid'); if($stmt){ $result = $stmt -> FETCHALL(PDO::FETCH_ASSOC); echo '<pre>'; var_dump($result); echo '</pre>'; } 写个留言板 排除重复的数据行 Select distinct name from user 查一个字段的重复值 select name,count(*) as num from user group by name having count(*) > 1 查出一个表的结果 然后写入另一个表 insert into haha (name,num) select A.name,A.num from (select name,count(*) as num from user group by name having num > 1) as A 查出一个公司的名称,并通过id关联的cid统计出另一张表的职位个数 select A.name,B.num from (select id,name from comname) as A,(select cid,count(*) as num from job group by cid) as B where A.id=B.cid 将数据库的一个字段存的时间戳 转换为 日期 select A.name,A.num,A.times from (select name,num,from_unixtime(num) as times from haha) as A 根据时间戳查出这个月的纪录 select A.name,A.num,A.times from (select name,num,date_format(from_unixtime(num),\'%y-%m-%d\') as times from haha) as A where A.times=date_format(now(),\'%y-%m-%d\'