7个超级实用的PHP代码片段分享(1)_PHP教程
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2022-05-25 15:19:14
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1、超级简单的页面缓存
如果你的工程项目不是基于 CMS 系统或框架,打造一个简单的缓存系统将会非常实在。下面的代码很简单,但是对小网站而言能切切实实解决问题。
- // define the path and name of cached file
- $cachefile = 'cached-files/'.date('M-d-Y').'.php';
- // define how long we want to keep the file in seconds. I set mine to 5 hours.
- $cachetime = 18000;
- // Check if the cached file is still fresh. If it is, serve it up and exit.
- if (file_exists($cachefile) && time() - $cachetime filemtime($cachefile)) {
- include($cachefile);
- exit;
- }
- // if there is either no file OR the file to too old, render the page and capture the HTML.
- ob_start();
- ?>
- output all your html here.
- // We're done! Save the cached content to a file
- $fp = fopen($cachefile, 'w');
- fwrite($fp, ob_get_contents());
- fclose($fp);
- // finally send browser output
- ob_end_flush();
- ?>
点击这里查看详细情况:http://wesbos.com/simple-php-page-caching-technique/
2、在 PHP 中计算距离
这是一个非常有用的距离计算函数,利用纬度和经度计算从 A 地点到 B 地点的距离。该函数可以返回英里,公里,海里三种单位类型的距离。
- function distance($lat1, $lon1, $lat2, $lon2, $unit) {
- $theta = $lon1 - $lon2;
- $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
- $dist = acos($dist);
- $dist = rad2deg($dist);
- $miles = $dist * 60 * 1.1515;
- $unit = strtoupper($unit);
- if ($unit == "K") {
- return ($miles * 1.609344);
- } else if ($unit == "N") {
- return ($miles * 0.8684);
- } else {
- return $miles;
- }
- }
使用方法:
- echo distance(32.9697, -96.80322, 29.46786, -98.53506, "k")." kilometers";
点击这里查看详细情况:http://www.phpsnippets.info/calculate-distances-in-php
3、将秒数转换为时间(年、月、日、小时…)
这个有用的函数能将秒数表示的事件转换为年、月、日、小时等时间格式。
- function Sec2Time($time){
- if(is_numeric($time)){
- $value = array(
- "years" => 0, "days" => 0, "hours" => 0,
- "minutes" => 0, "seconds" => 0,
- );
- if($time >= 31556926){
- $value["years"] = floor($time/31556926);
- $time = ($time%31556926);
- }
- if($time >= 86400){
- $value["days"] = floor($time/86400);
- $time = ($time%86400);
- }
- if($time >= 3600){
- $value["hours"] = floor($time/3600);
- $time = ($time%3600);
- }
- if($time >= 60){
- $value["minutes"] = floor($time/60);
- $time = ($time%60);
- }
- $value["seconds"] = floor($time);
- return (array) $value;
- }else{
- return (bool) FALSE;
- }
- }
点击这里查看详细情况:http://ckorp.net/sec2time.php
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