Server Side Programming Articles - Page 1914 of 2646

Until now, you have been reading and writing to the standard input and output. Now, we will see how to interact with actual data files. Python provides built-in functions and methods necessary to manipulate files by default. To work with a file in Python, we first need to create a file object. Using this object you can do most of the file manipulation such as reading, writing, or closing a file. Opening a File in Python Before you can read or write a file, you have to open it using Python's built-in open() function. This function creates a file object, ... Read More

Reading keyboard input in Python can be easily done by using the built-in functions. Python provides two built-in functions to read a line of text from standard input, which by default comes from the keyboard. These functions are: raw_input() input() Using the raw_input() Function The Python raw_input() function reads keyboard input and returns it as a string (removing the trailing newline). It is important to note that this function is available for the Python 2.x version only. It was renamed to input() in the Python 3.x versions. Example Let's take ... Read More

Printing to the Screen in Python In Python, the print() function is used to display the data on the screen. The data can be a string or any other object. However, the resultant object will be converted into a string before printing it on the console or standard output device. In this article let's understand a brief about print() function with various operations. Syntax of print() Function Following is the syntax of the print() function in Python − print(value(s), sep= ‘ ‘, end = ‘’, file=file, flush=flush) Following are the parameters of the print() function − ... Read More

The globals() and locals() are the Python built-in functions that are used to return the names in the global and local namespaces, depending on the location from where they are called. Whereas the reload() method is used to manage the Python modules. The globals() Function The globals() function in Python is used to get a dictionary representing the global namespace, containing all the global variables and their corresponding values in the current scope. If globals() is called from within a function, it will return all the names that can be accessed globally from that function. Example The following example demonstrates ... Read More

Variables are names (identifiers) that map to objects. A namespace is a dictionary of variable names (keys) and their corresponding objects (values).A Python statement can access variables in a local namespace and in the global namespace. If a local and a global variable have the same name, the local variable shadows the global variable.Each function has its own local namespace. Class methods follow the same scoping rule as ordinary functions.Python makes educated guesses on whether variables are local or global. It assumes that any variable assigned a value in a function is local.Therefore, in order to assign a value to a global variable within a ... Read More

Locating modules in Python refers to the process of how Python finds and loads a module into our current program when we are trying to import it. Python's standard library comes with a large number of modules that we can use in our programs with the import statement. Locating Modules in Python When you write an import statement like import mymodule, the Python interpreter searches for the module in the following sequences: The current directory: Python first checks the directory of the current script. PYTHONPATH Environment Variable: If the module isn't ... Read More

In Python, accessing and using the code from one module to another module is possible by the importing process. That means, you can use any Python source file as a module by executing an import statement in some other Python source file. This is done using the import statement in Python. The import Statement When the Python interpreter encounters an import statement, it imports the module if the module is present in the search path. A search path is a list of directories that the interpreter searches before importing a module. This import operation in Python internally uses the built-in ... Read More

The return statement in python is an extremely useful statement used to return the flow of program from the function to the function caller. The keyword return is used to write the return statement. Since everything in python is an object the return value can be any object such as – numeric (int, float, double) or collections (list, tuple, dictionary) or user defined functions and classes or packages. The return statement has the following features - Return statement cannot be used outside the function. Any code written after return statement is called dead code as it will never ... Read More

The Anonymous Functions in Python Python creates function objects when you write a lambda expression using the lambda keyword. These functions are called anonymous functions because they are not defined using the standard def keyword. These functions are useful when you need a small, single-line function to execute a single expression. Features of Anonymous Functions The following are the features of Anonymous Functions: It can be used wherever a function object is needed in your program, without assigning a name. A lambda function can take any number of arguments but can only ... Read More

You may need to process a function for more arguments than you specified while defining the function. These arguments are called variable-length arguments and are not named in the function definition, unlike required and default arguments.SyntaxSyntax for a function with non-keyword variable arguments is this −def functionname([formal_args, ] *var_args_tuple ): "function_docstring" function_suite return [expression]An asterisk (*) is placed before the variable name that holds the values of all nonkeyword variable arguments. This tuple remains empty if no additional arguments are specified during the function call.Example Live Demo#!/usr/bin/python # Function definition is here def printinfo( arg1, *vartuple ): "This prints a variable passed arguments" ... Read More