echo 'a test by array_key_exists: ' , array_key_exists('a', $a) ? 'exist' : 'not exist', PHP_EOL, PHP_EOL;echo 'b test by empty: ' , empty($a['b']) ? 'not exist' : 'exist', PHP_EOL;echo 'b test by isset: ' , isset($a['b']) ? 'exist' : 'not exist', ...
可以看到在大数据情况下,empty和isset的性能比array_key_exists快了2个数量级,差别还是很大。如果频繁判断,还是需要优化。产生这么大性能差别的原因,个人猜测,可能是isset和empty作为php语法结构不是函数,php解释器做了优化,而array_key_exists作为函数,没有相关优化。具体原因,有待通过源码考究。
$array = ['apple', 'banana', 'orange']; // 使用 in_array() if (in_array('banana', $array)) { echo 'Banana exists'; } // 严格模式检查(类型也匹配) if (in_array('1', $array, true)) { echo 'Strict match found'; } 3. 检查元素是否为空 php $value = ''; if (empty($va...
$emptyArray=[]; $emptyArray=array(); $emptyArray=(array)null; 将元素推送到数组时,可以使用$emptyArray[]=“first”。此时,$emptyArray包含“first”,使用此命令并将“first”发送到数组,该数组在启动时声明为空。 换句话说,新数组的初始化速度更快,使用语法varfirst=[]而不是使用语法varfirst=newArray(...
($heapArr)-1]);//array_pop也可以用这个代替//重新调整堆顶$heapArr=$this->_adjustHeapArray($heapArr);}return$arrRes;}//根据一维数组构造二叉堆privatefunction_getHeapArray(array$arr=array()){if(empty($arr)){return$arr;}$heapArr=array();$arrLength=count($arr);for($i=0;$i<$arr...
$localfile = "D:\\localpath\\examplefile.txt"; $options = array( OssClient::OSS_FILE_DOWNLOAD => $localfile ); // 使用try catch捕获异常。如果捕获到异常,则说明下载失败;如果没有捕获到异常,则说明下载成功。 try{ $config = array( "provider" => $provider, "endpoint" => $endpoint, "si...
/*** 获取和设置配置参数 支持批量定义* @param string|array $name 配置变量* @param mixed $value 配置值* @param mixed $default 默认值* @return mixed*/function C($name = null, $value = null, $default = null){static $_config = array();// 无参数时获取所有if (empty($name)) {return...
if(in_array($typeCode,$_typecode) || $_count== 1) { returntrue; }else{ returnfalse; } } 九.获取用户真实的IP function getRealIpAddr() { if (!emptyempty($_SERVER['HTTP_CLIENT_IP'])) { $ip=$_SERVER['HTTP_CLIENT_IP']; ...
Check these helpful resources: Step 1 Installation The primary way of installing Yii is by using Composer. Install Composer Get a basic project template Run./yii serve Step 2 Welcome Page You get a nice template which includes: MVC Some static pages ...
The yii\helpers\Url::to() method also supports creating URLs that are not related with particular routes. Instead of passing an array as its first parameter, you should pass a string in this case. For example,use yii\helpers\Url; // currently requested URL: /index.php?r=admin%2Fpost%...