isset

I am tired of using code like: $blog = isset($_GET['blog']) ? $_GET['blog'] : 'default'; but I can't use: $blog = $_GET['blog'] || 'default'; Is there any way to do this without using isset() ? You have to wait for the next version of PHP to get the coalesce operator // Uses $_GET['user'] if it exists -- or 'nobody' if it doesn't $username = $_GET['user'] ?? 'nobody'; // Loads some data from the model and falls back on a default value $model = Model::get($id) ?? $default_model; Write a helper function. function arrayValue($array, $key, $default = null) { return isset($array[$key]) ? $array[

According to php documentation, the following expressions return true when calling empty($var) "" (an empty string) 0 (0 as an integer) 0.0 (0 as a float) "0" (0 as a string) NULL FALSE array() (an empty array) $var; (a variable declared, but without a value) i've found how to "solve" the problem by using empty($var) && $var != 0 but why php developers did it? i think it is ridiculous, suppouse you have this code: if (empty($_POST["X"])) { doSomething(); } i think "0" is not empty, empty is when there is nothing!!! maybe it's better to use if (isset($x) && x != "") {//for strings doSomething()

class a { function __get($property){...} } $obj = new a(); var_dump(isset($obj->newproperty)); Seems the answer is nope but why? Because it checks __isset rather than retrieving it using __get. It is a much better option to call __isset, as there is no standard on what is empty. Maybe in the context of the class null is an acceptable value. You could also have a class that if the member didn't exist, it returned a new empty object, which would break isset($myObj->item) as in that case it would always return true. It just isn't; you can use __isset instead. This is laid out here . No, __get

PHP脚本可以与HTML表单一起使用，以允许用户将文件上载到服务器。最初将文件上载到临时目录中，然后通过PHP脚本重定位到目标目标。phpinfo.php页面中的 upload_tmp_dir 信息将用于文件上载的临时目录，并且可以上载的文件的最大允许大小表示为 upload_max_filesize 。这些参数在PHP配置文件 php.ini 中设置。 上传文件的过程遵循以下步骤 以下HTM代码创建一个上传器表单。此表单将方法属性设置为post，并将enctype属性设置为multipart/form-data <?php if(isset($_FILES['image'])){ $errors= array(); $file_name = $_FILES['image']['name']; $file_size = $_FILES['image']['size']; $file_tmp = $_FILES['image']['tmp_name']; $file_type = $_FILES['image']['type']; $name_arr = explode('.',$_FILES['image']['name']); $file_ext=strtolower(end($name_arr)); $extensions= array("jpeg","jpg","png");

常用函数 函数: 将多个代码封装到一起, 形成一个完整的功能. 基本格式: 函数名() empty() 检测一个变量是否为空 (只要与false等价的都认为是空) isset() 检测一个变量是否设置 (只要值显示为null的都是没设置的) 设置: true 没设置: false unset() 释放(删除)一个变量 <?php $a = 0 ; $a = 0.0 ; $a = '' ; $a = '0' ; $a = '00' ; $a = null ; $a = [ ] ; $a = 1 ; var_dump ( empty ( $a ) ) ; echo '<hr>' ; $a = null ; $a = 0 ; $a = false ; var_dump ( isset ( $a ) ) ; var_dump ( isset ( $xxx ) ) ; ?> 来源： CSDN 作者： weixin_44516932 链接： https://blog.csdn.net/weixin_44516932/article/details/103124721

I have found that array_key_exists is over 1000x slower than isset at check if a key is set in an array reference. Does anyone that has an understanding of how PHP is implemented explain why this is true? EDIT: I've added another case that seems to point to it being overhead required in calling functions with a reference. Benchmark Example function isset_( $key, array $array ) { return isset( $array[$key] ); } $my_array = array(); $start = microtime( TRUE ); for( $i = 1; $i < 10000; $i++ ) { array_key_exists( $i, $my_array ); $my_array[$i] = 0; } $stop = microtime( TRUE ); print "array_key

Is there a way to check if an array index exists or is null ? isset() doesn't tell you whether the index doesn't exist or exists but is null. If I do : isset($array[$index]) || is_null($array[$index]) it won't work because if the index doesn't exist is_null will crash. How can I check this please? Also is there a way to check only if something exist, no matter if it is set to null or not? Virus721 The function array_key_exists() can do that, and property_exists() for objects, plus what Vineet1982 said. Thanks for your help. This is the very good question and you can use get_defined_vars() for