Defined or define in PHP [duplicate]

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6 Answers

definedefined
90%

My questions is : What is the purpose of this line of code? There are no conditional statements such as if, switch. Does it imply a conditional statement automatically? ,You'll also often see short circuit evaluation with the && operator. One example of this is a common idiom used in many languages is to NULL check in the if statement by checking for NULL first in the && expression:,This works the opposite of || short circuit evaluation. For && evaluation stops if the first argument is false, because everything must be true for the && to pass. So in the above code, something->SomeCondition() won't cause any kind of crash if something is NULL -- it won't get executed because something != NULL was false and execution of the expression terminated at that point., By clicking “Accept all cookies”, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.

Your assumption is correct. This is just a short hand way of saying

if (!defined('APPLICATION_PATH')) {
   define('APPLICATION_PATH', '...');
}

You can easily test this:

define("foo", "bar");
defined("foo") || define("foo", "baz");
var_dump(foo);

Output is bar.

//define("foo", "bar");
defined("foo") || define("foo", "baz");
var_dump(foo);
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88%

When an object is cloned, PHP will perform a shallow copy of all of the object's properties. Any properties that are references to other variables will remain references. , Once the cloning is complete, if a __clone() method is defined, then the newly created object's __clone() method will be called, to allow any necessary properties that need to be changed. , An object copy is created by using the clone keyword (which calls the object's __clone() method if possible). , It is possible to access a member of a freshly cloned object in a single expression:

$copy_of_object = clone $object;
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72%

The clone keyword is used to create a copy of an object.,Create a copy of an object:,Create a copy of an object which has a reference:,Use a __clone() method to break references in a copied object:

Definition and Usage

The clone keyword is used to create a copy of an object.

clone
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65%

Not sure how to use foreach loops in PHP? Using references in foreach loops can be useful if you want to operate on each element in the array that you are iterating over. For example:,Another example when empty() can be dangerous is when combining it with the magic class function __get(). Let’s define two classes and have a test property in both.,But the same thing can be accomplished much more efficiently in a single SQL query as follows:,If you don’t know much about Unicode and UTF-8, you should at least learn the basics. There’s a great primer here.

Not sure how to use foreach loops in PHP? Using references in foreach loops can be useful if you want to operate on each element in the array that you are iterating over. For example:

$arr = array(1, 2, 3, 4);
foreach($arr as & $value) {
   $value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
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75%

Files that define symbols should not cause side-effects Bug,WordPress options should not be defined at the end of "wp-config.php" Code Smell,WordPress option names should not be misspelled Code Smell,Comments should not be located at the end of lines of code Code Smell

With the default threshold of 3:

function run() {
   prepare('this is a duplicate'); // Non-Compliant - 'this is a duplicate' is duplicated 3 times
   execute('this is a duplicate');
   release('this is a duplicate');
}
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40%

Meaning, the contained objects of the copied objects are not copied. If you wish for a deep copy, then you need to define the __clone() method.,Object cloning is creating a copy of an object. An object copy is created by using the clone keyword and the __clone() method cannot be called directly. In PHP, cloning an object is doing a shallow copy and not a deep copy.,To perform a deep copy while cloning in PHP, then you can either overwite __clone method in the copied object’s class or serialize and unserialize the object as done below.,In the below example, we are copying objects by using PHP clone keyword. PHP’s clone method does a shallow copy and so, any changes made in the cloned object will not affect original object.

So, this type of copy is just a duplicate reference to the original instance. Technically this is not a copy, but it is just assigning the object’s reference to another object.

< ? php
class Animals {
   public $name;
   public $category;
}
//Creating instance of Animals class
$objAnimals = new Animals();
//setting properties
$objAnimals - > name = "Lion";
$objAnimals - > category = "Wild Animal";
//Copying object
$objCopied = $objAnimals;
$objCopied - > name = "Cat";
$objCopied - > category = "Pet Animal"
print_r($objAnimals);
print_r($objCopied); ?
>
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