


PHP sorting algorithm class examples, sorting algorithm examples
The examples in this article describe the PHP sorting algorithm class. Share it with everyone for your reference. The details are as follows:
PHP implementation of four sorting algorithms:
1) The basic idea of Insertion Sort is:
Each time a record to be sorted is inserted into the appropriate position in the previously sorted sub-file according to its key size, until all records are inserted.
2) The basic idea of Selection Sort is:
In each pass, the record with the smallest keyword is selected from the records to be sorted and placed at the end of the sorted sub-file until all records are sorted.
3) The basic idea of bubble sort is:
Compare the keys of the records to be sorted pairwise, and if it is found that the order of the two records is reversed, they will be exchanged until there are no records in the reverse order.
4) Quick sort is essentially the same as bubble sort, and is an application of exchange sort. So the basic idea is the same as the bubble sort above.
1. The sort.php file is as follows:
<?php /** * * @author quanshuidingdang */ class Sort { private $arr = array(); private $sort = 'insert'; private $marker = '_sort'; private $debug = TRUE; /** * 构造函数 * * @param array 例如: $config = array ( 'arr' => array(22,3,41,18) , //需要排序的数组值 'sort' => 'insert', //可能值: insert, select, bubble, quick 'debug' => TRUE //可能值: TRUE, FALSE ) */ public function __construct($config = array()) { if ( count($config) > 0) { $this->_init($config); } } /** * 获取排序结果 */ public function display() { return $this->arr; } /** * 初始化 * * @param array * @return bool */ private function _init($config = array()) { //参数判断 if ( !is_array($config) OR count($config) == 0) { if ($this->debug === TRUE) { $this->_log("sort_init_param_invaild"); } return FALSE; } //初始化成员变量 foreach ($config as $key => $val) { if ( isset($this->$key)) { $this->$key = $val; } } //调用相应的成员方法完成排序 $method = $this->sort . $this->marker; if ( ! method_exists($this, $method)) { if ($this->debug === TRUE) { $this->_log("sort_method_invaild"); } return FALSE; } if ( FALSE === ($this->arr = $this->$method($this->arr))) return FALSE; return TRUE; } /** * 插入排序 * * @param array * @return bool */ private function insert_sort($arr) { //参数判断 if ( ! is_array($arr) OR count($arr) == 0) { if ($this->debug === TRUE) { $this->_log("sort_array(insert)_invaild"); } return FALSE; } //具体实现 $count = count($arr); for ($i = 1; $i < $count; $i++) { $tmp = $arr[$i]; for($j = $i-1; $j >= 0; $j--) { if($arr[$j] > $tmp) { $arr[$j+1] = $arr[$j]; $arr[$j] = $tmp; } } } return $arr; } /** * 选择排序 * * @param array * @return bool */ private function select_sort($arr) { //参数判断 if ( ! is_array($arr) OR count($arr) == 0) { if ($this->debug === TRUE) { $this->_log("sort_array(select)_invaild"); } return FALSE; } //具体实现 $count = count($arr); for ($i = 0; $i < $count-1; $i++) { $min = $i; for ($j = $i+1; $j < $count; $j++) { if ($arr[$min] > $arr[$j]) $min = $j; } if ($min != $i) { $tmp = $arr[$min]; $arr[$min] = $arr[$i]; $arr[$i] = $tmp; } } return $arr; } /** * 冒泡排序 * * @param array * @return bool */ private function bubble_sort($arr) { //参数判断 if ( ! is_array($arr) OR count($arr) == 0) { if ($this->debug === TRUE) { $this->_log("sort_array(bubble)_invaild"); } return FALSE; } //具体实现 $count = count($arr); for ($i = 0; $i < $count; $i++) { for ($j = $count-1; $j > $i; $j--) { if ($arr[$j] < $arr[$j-1]) { $tmp = $arr[$j]; $arr[$j] = $arr[$j-1]; $arr[$j-1] = $tmp; } } } return $arr; } /** * 快速排序 * * @param array * @return bool */ private function quick_sort($arr) { //具体实现 if (count($arr) <= 1) return $arr; $key = $arr[0]; $left_arr = array(); $right_arr = array(); for ($i = 1; $i < count($arr); $i++){ if ($arr[$i] <= $key) $left_arr[] = $arr[$i]; else $right_arr[] = $arr[$i]; } $left_arr = $this->quick_sort($left_arr); $right_arr = $this->quick_sort($right_arr); return array_merge($left_arr, array($key), $right_arr); } /** * 日志记录 */ private function _log($msg) { $msg = 'date[' . date('Y-m-d H:i:s') . '] ' . $msg . '\n'; return @file_put_contents('sort_err.log', $msg, FILE_APPEND); } } /*End of file sort.php*/ /*Location htdocs/sort.php */
2. The sort_demo.php file is as follows:
<?php require_once('sort.php'); $config = array ( 'arr' => array(23, 22, 41, 18, 20, 12, 200303,2200,1192) , //需要排序的数组值 'sort' => 'select', //可能值: insert, select, bubble, quick 'debug' => TRUE //可能值: TRUE, FALSE ); $sort = new Sort($config); //var_dump($config['arr']); var_dump($sort->display()); /*End of php*/
I hope this article will be helpful to everyone’s PHP programming design.

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。


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