You can use a finally: block along with a try: block. The finally block is a place to put any code that must execute, whether the try-block raised an exception or not. The syntax of the try-finally statement is this −try:    You do your operations here;    ......................    Due to any exception, this may be skipped. finally:    This would always be executed.    ......................You cannot use else clause as well along with a finally clause.Example Live Demo#!/usr/bin/python try:    fh = open("testfile", "w")    fh.write("This is my test file for exception handling!!") finally:    print "Error: can\'t find file or read ... Read More

In Python, by using different methods we can find the longest substring without repeating characters, such as by using the Brute force approach which involves checking all the Substrings, and also by using the advanced Sliding window Two Pointer approach, which uses a Hashmap to store the indexes. Some Common Methods Some of the common approaches in Python to find the longest Substring Without Repeating Characters are as follows. Brute Force: Checks all possible substrings and verifies if they have all unique characters in the string. Sliding Window with Set: This approach tracks characters in the current substring ... Read More

An assertion is a sanity-check that you can turn on or turn off when you are done with your testing of the program.The easiest way to think of an assertion is to liken it to a raise-if statement (or to be more accurate, a raise-if-not statement). An expression is tested, and if the result comes up false, an exception is raised.Assertions are carried out by the assert statement, the newest keyword to Python, introduced in version 1.5.Programmers often place assertions at the start of a function to check for valid input, and after a function call to check for valid ... Read More

Adding two numbers in Python is one of the most basic tasks, where we need to combine their values to get a total. In this article, we will see different ways to add two numbers in Python. Using Arithmetic Operator To add two numerical values in Python, we can use the addition operation, represented by the "+" symbol. It is one of the arithmetic operators in Python that performs the addition operation. Example Here is the basic example that adds the two numbers using the addition operator (+). # Assign values to the variables a = 7 b = ... Read More

Locating file positions in Python means identifying the current position of the file pointer within an open file. Python provides the tell() and seek() methods of the file object for this task. Locating the File Position The tell() method tells you the current position within the file. In other words, it specifies that the next read or write will occur at that many bytes from the beginning of the file. Example The following example shows how to get the current file position using the tell() method. Initially, when a file is opened, the pointer is placed at the beginning. After ... Read More

Reading data from a file and writing to a file can be easily done in Python by using the file object. The file object in Python provides a set of methods for handling files. These methods make our lives easier for interacting with files on our computer. Below, we will see how to read and write files in Python using the read() and write() methods. The write() Method The write() method writes any string to an opened file. It is important to note that Python strings can have binary data and not just text. This method does not add a ... Read More

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