Short Answer Use $this to refer to the current object. Use self to refer to the current class. In other words, use $this->member for non-static members, use self::$member for static members. Full Answer Here is an example of correct usage of $this and self for non-static and static member variables: <?php class X { private … Read more
What is the correct usage of session scope Use it for session scoped data only, nothing else. For example, the logged-in user, its settings, the chosen language, etcetera. See also: How to choose the right bean scope? And every time I visit the page, the product list will be created from the latest entries in … Read more
echo -e $lines | while read line … done The while loop is executed in a subshell. So any changes you do to the variable will not be available once the subshell exits. Instead you can use a here string to re-write the while loop to be in the main shell process; only echo -e … Read more
JavaScript has no classes class-based object model. It uses the mightier prototypical inheritance, which can mimic classes, but is not suited well for it. Everything is an object, and objects [can] inherit from other objects. A constructor is just a function that assigns properties to newly created objects. The object (created by a call with … Read more
Function hoisting means that functions are moved to the top of their scope. That is, function b() { a = 10; return; function a() {} } will be rewritten by the interpeter to this function b() { function a() {} a = 10; return; } Weird, eh? Also, in this instance, function a() {} behaved … Read more
Class scope and list, set or dictionary comprehensions, as well as generator expressions do not mix. The why; or, the official word on this In Python 3, list comprehensions were given a proper scope (local namespace) of their own, to prevent their local variables bleeding over into the surrounding scope (see List comprehension rebinds names … Read more
The nested function looks up variables from the parent scope when executed, not when defined. The function body is compiled, and the ‘free’ variables (not defined in the function itself by assignment), are verified, then bound as closure cells to the function, with the code using an index to reference each cell. pet_function thus has … Read more
Python doesn’t have variable declarations, so it has to figure out the scope of variables itself. It does so by a simple rule: If there is an assignment to a variable inside a function, that variable is considered local.[1] Thus, the line counter += 1 implicitly makes counter local to increment(). Trying to execute this … Read more
Python treats variables in functions differently depending on whether you assign values to them from inside or outside the function. If a variable is assigned within a function, it is treated by default as a local variable. Therefore, when you uncomment the line, you are trying to reference the local variable c before any value … Read more
Break the chain When you need to access the intermediate values in your chain, you should split your chain apart in those single pieces that you need. Instead of attaching one callback and somehow trying to use its parameter multiple times, attach multiple callbacks to the same promise – wherever you need the result value. … Read more