Found 27104 Articles for Server Side Programming

Python allows you to save definitions to a file and then use them in a script or interactive instance of the interpreter. A module is a file that contains definitions that can be imported into other modules or the main module. So, a Python module is nothing more than a package that contains reusable code. Modules are stored in a folder that contains a __init .py file. Modules can contain both functions and classes. The import keyword is used to import modules. A file containing Python commands and definitions is referred to as a module. These files named .py ... Read More

Namespaces in Python and C++ cannot really be compared. For example, in C++ −// a.h namespace ns {     struct A { .. };     struct B { .. }; }If we were to do this −#include "a.h" using ns::A;The point of that code is to be able to write A unqualified(ie, not having to write ns::A). Now, you might consider a python equivalent as −from a import ABut regardless of the using, the entire a.h header will still be included and compiled, so we would still be able to write ns::B, whereas in the Python version, a.B ... Read More

Globals in Python are global to a module, not across all modules. (Unlike C, where a global is the same across all implementation files unless you explicitly make it static.). If you need truly global variables from imported modules, you can set those at an attribute of the module where you're importing it.import module1 module1.a=3On the other hand, if a is shared by a whole lot of modules, put it somewhere else, and have everyone import it:global_module.py module1.py: import global_module def fun():     print global_module.var Other files: import global_module import module1 global_module.var = 3 module1.fun()Read More

It is a bad idea to be importing everything from a Python package as a package is not a super-module -- it's a collection of modules grouped together. So you should just import what you need in that file. Also importing everything from package into your global namespace is going to cause a proliferation of names, and very likely conflicts among those names.That being said, there are still ways to do this. First one being manually importing everything from a package using import statements for every sub-module.  Another way, as the documentation at http://docs.python.org/tutorial/modules.html#importing-from-a-package - suggests, is that if you ... Read More

The "from module import *" statement is used to import all submodules from a Python package/module. For example, if you want to import all modules from your module(say nyModule) and do not want to prefix "myModule." while calling them, you can do it as follows:>>> from myModule import *Note that for any reasonable large set of code, if you import * you will likely be cementing it into the module, unable to be removed. This is because it is difficult to determine what items used in the code are coming from 'module', making it easy to get to the point ... Read More

Using namespace packages, you can distribute the sub-packages and modules of one package among many, independent distribution packages (referred to as distributions in this document to avoid ambiguity). In Python, a namespace package allows you to spread Python code among several projects. This is useful when you want to release related libraries as separate downloads. Creating a namespace package Currently, there are three methods for developing namespace packages. These methods are mentioned below. Use packages for native namespaces. The PEP 420 specification for this kind of namespace package states that Python 3.3 and later support it. If packages in ... Read More

This is basically the idea of a singleton object. So if you have instantiated an obect and want to access it across different module, you can use 2 approaches, first being you assign that variable to the module you imported under a variable name. For example, you have a object myobj instantiated and want to use it with module B, then you can do the following:>>> import B >>> B.myobj = myobjAnd inside module B, use it like any other global property. Another way is to accept this object as a parameter wherever required. For example, if you have a ... Read More

Yes, a function call (any function call, not just recursive ones) creates a new namespace. BUT, when given as parameters, OBJECTS are passed by reference.So, the new namespace get its own copy of this reference but it still refers to the same object as in the calling function, and if you change the content of that object, you will notice the change in the calling function.To be more specific, Whenever the Interpreter encounters a call to a function, its creates a frame object, which is pushed to a frame stack. Each time a frame is created, that frame is given ... Read More

Namespace is a way to implement scope. In Python, each package, module, class, function and method function owns a "namespace" in which variable names are resolved. When a function,  module or package is evaluated (that is, starts execution), a namespace is created. Think of it as an "evaluation context". When a function, etc., finishes execution, the namespace is dropped. The variables are dropped. Plus there's a global namespace that's used if the name isn't in the local namespace.Each variable name is checked in the local namespace (the body of the function, the module, etc.), and then checked in the global ... Read More

This article explains what the Python code expression if __name__ == '__main__' means. A Python programme uses the condition if __name__ == '__main__' to only run the code inside the if statement when the program is run directly by the Python interpreter. The code inside the if statement is not executed when the file's code is imported as a module. What is __main__? The word "__name__" denotes a unique variable in Python. Python has a large number of special variables that begin and end with double underscores. They are referred to as dunder to keep it brief (from Double Underscores). ... Read More