PHP Face Question Collection 2

1, the realization of Chinese character string interception without garbled method

Open the mbstring extension, and then customize the function:

<?phpheader (' content-type:text/html:charset=utf-8 '); function Substr_utf8 ($str, $start, $length = null) {return Join ("", Array_slice (Preg_split ("//u", $str,-1, Preg_split_no_empty), $start, $length));} Example $STR = "I am a good boy!"; Echo Substr_utf8 ($str, 2, 4);

2. Print the day before using PHP

<?phpheader (' content-type:text/html:charset=utf-8 '); Echo date (' y-m-d h:i:s ', Strtotime ('-1 day '));

3, does not apply the third variable Exchange 2 variables value

<?phpheader (' content-type:text/html:charset=utf-8 '); $a = ' a '; $b = ' B '; list ($a, $b) = Array ($b, $a); Echo $a, $b;

4. Convert 1234567890 to 1,234,567,890

Header (' Content-type:text/html:charset=utf-8 '); $str = ' 1234567890 ';//invert string $str = Strrev ($STR);//Comma separated by 098, 765,432,1, $str = Chunk_split ($str, 3, ', ');//Invert $str = Strrev ($STR);//Remove Left, $str = LTrim ($str, ', '); Echo $str;

5. Implement UTF8 string inversion

Cannot use Strrev, Chinese will be wrong

function Strrev_utf8 ($STR) {return join ("", Array_reverse (Preg_split ("//u", $str)));} $str = "I am a good boy"; Echo Strrev_utf8 ($STR);

6, take the URL file extension, as much as possible to implement the method

$str = "www.baidu.com/index.php"; function Get_ext1 ($STR) {return strrchr ($str, '. ');} function Get_ext2 ($str) {return substr ($str, Strrpos ($str, '. '));} function Get_ext3 ($str) {$str = PathInfo ($STR); return $str [' extension '];} function Get_ext4 ($str) {$arr = explode ('. ', $str); return $arr [Count ($arr)-1];} function Get_ext5 ($str) {$pattern = '/^[^\.] +\. ([\w]+) $/'; return preg_replace ($pattern, ' ${1} ', basename ($STR));}

7. Write a function to convert the string Open_door to Opendoor

$str = "Open_door", function Change_str ($str) {$arr = explode (' _ ', $str); $arr = Array_map (' Ucfirst ', $arr); return implode ( ", $arr);} echo Change_str ($STR);

8. Single case mode

<?phpclass mysql{private static $instance = Null;private $conn;//set to private, do not allow object private function through new __construct () {$ conn = mysql_connect (' localhost ', ' root ', ' 123456 ');} Gets the instance method public static function getinstance () {if (! Self:: $instance instanceof Self) {self:: $instance = new Self;} Return self:: $instance;} Disallow cloning of private function __clone () {}} $db = Mysql::getinstance ();

9. Write a PHP code to ensure that multiple processes write to the same file successfully

<?PHP$FP = fopen ("Lock.txt", "w+"), if (Flock ($FP, LOCK_EX)) {//Get write lock fwrite ($fp, ' write something '); Flock ($FP, Lock_un );} Else{echo "File is locking ...";} Fclose ($FP);

10. Get the file name extension from a completed URL

<?php$url = ' http://www.baidu.com/a/b/index.php?id=1 '; $arr = Parse_url ($url); $fname = basename ($arr [' path ']); $arr = Explode ('. ', $fname); Echo $arr [Count ($arr)-1];

11. Write a function to facilitate all files and subfolders under a folder

<?phpfunction My_scandir ($dir) {$files = array (), if (Is_dir ($dir)) {if ($handle = Opendir ($dir)) {while ($file = Readdir ($handle))!== false) {if ($file! = "." && $file! = "...") {if (Is_dir ($dir. '/'. $file)) {$files [$file] = My_scandir ($dir. '/'. $file);} else{$files [] = $dir. '/'. $file;}}} Closedir ($handle); return $files;}}} Var_dump (My_scandir (' D:\wamp\www\study '));

12. The principle of unlimited classification in the forum

First design the database table

CREATE TABLE category (cate_id int unsigned not NULL auto_increment primary key,cat_name varchar (in) NOT null default ', PA rent_id int unsigned NOT NULL default 0) Engine=innodb Charset=utf8;

Then use the function to recursively implement, infinite classification

function tree ($arr, $pid =0, $level =0) {Static $list = array (); foreach ($arr as $v) {///if it is a top-level classification, the $list//is then placed at this node as the root, Traverse its child nodes if ($v [' parent_id '] = = $pid) {$v [' level '] = $level; $list [] = $v; tree ($arr, $v [' cat_id '], $level + 1)}} return $list;}

13, calculate the relative path of 2 files

<?php$a = '/a/b/c/d/a.php '; $b = '/a/b/e/f/b.php '; $arr 1 = explode ('/', dirname ($a)), $arr 2 = explode ('/', dirname ($b)); For ($i =0, $len =count ($arr 2), $i < $len, $i + +) {if ($arr 1[$i]! = $arr 2[$i]) {break;}} Not in a root directory if ($i = = 1) {$ret = Array ();} Under the same root directory if ($i! = 1 && $i < $len) {$ret = Array_fill (0, $len-$i, "..");} Under the same directory if ($i = = $len) {$ret = Array ('./');} $ret = Array_merge ($ret, Array_slice ($arr 1, $i)); Echo implode ('/', $ret);

14. Joseph Ring Question

<?phpfunction King ($n, $m) {$monkey = range (1, $n), $i = 0;while (count ($monkey) > 1) {$i + = 1; $head = Array_shift ($monke y);//To the front of the first if ($i% $m! = 0) {//If it is not a multiple of M, then return to the tail, otherwise the Array_push ($monkey, $head);}} return $monkey [0];} echo King (10,7);

15, PHP implementation of two-way queue

<?phpclass dqueue{private $queue = Array ();p ublic function AddFirst ($item) {return Array_unshift ($this->queue,$ Item);} Public Function AddLast ($item) {return Array_push ($this->queue, $item);} Public Function GetFirst () {return array_shift ($this->queue);} Public Function GetLast () {return Array_pop ($this->queue);}}

PHP Face Question Collection 2