Python Articles - Page 937 of 1048

Python Object Persistence  The shelve module in Python's standard library is a simple yet effective tool for persistent data storage when using a relational database solution is not required. The shelf object defined in this module is a dictionary-like object persistently stored in a disk file. This creates a file similar to dbm database on UNIX-like systems. The only string data type can be used as a key in this special dictionary object, whereas any pickable object can serve as value. The shelve module defines three classes as follows − ... Read More

To install python MySQLdb module, we need to install Python current version i.e. 3.7 We need to find the location of Python Scripts where pip command is located. First, open the cmd and reach the location of Python Scripts. To open cmd, press “Windows+R” and type cmd. Here is the snapshot − Now reach where scripts are located. We will now install “MySQLdb” module. The steps are displayed in the following screenshot.

Like other languages, Python also has some reserved words. These words hold some special meaning. Sometimes it may be a command, or a parameter etc. We cannot use keywords as variable names. The Python Keywords are True False class def return if elif else try except raise finally for in is not from import global lambda nonlocal pass while break continue and with as yield del or assert None The True & False Keywords The True and False are the truth ... Read More

Python can handle the precision of floating point numbers using different functions. Most functions for precision handling are defined in the math module. So to use them, at first we have to import the math module, into the current namespace. import math Now we will see some of the functions for precision handling. The trunc() function The trunc() method is used to remove all fractional part from a floating point number. So it returns only the integer part from the number. The ceil() function The ceil() method is used to return the Ceiling value of a ... Read More

In this section, we will see how to print formatted texts in Linux terminal. By formatting, we can change the text color, style, and some special features. Linux terminal supports some ANSI escape sequences to control the formatting, color and other features. So we have to embed some bytes with the text. So when the terminal is trying to interpret them, those formatting will be effective. The general syntax of ANSI escape sequence is like below − \x1b[A;B;C A is the Text Formatting Style B is the Text Color or Foreground Color C is the Background ... Read More

Like other languages, Python provides some inbuilt functions for reading, writing, or accessing files. Python can handle mainly two types of files. The normal text file and the binary files. For the text files, each lines are terminated with a special character '' (It is known as EOL or End Of Line). For the Binary file, there is no line ending character. It saves the data after converting the content into bit stream. In this section we will discuss about the text files. File Accessing Modes Sr.No Modes & Description 1 r It is Read ... Read More

The graphs can be implemented using Dictionary in Python. In the dictionary, each key will be the vertices, and as value, it holds a list of connected vertices. So the entire structure will look like Adjacency list of a graph G(V, E). We can use the basic dictionary object, but we are using default dict. It has some additional features. It has one additional writable instance variable. We are providing a text file, which contains the number of vertices, number of edges, names of vertices, and the list of edges. For undirected graph, we are providing two edges like ... Read More

List is one of the built-in data types in Python, which is a sequence of comma-separated items, enclosed in square brackets [ ]. For example, consider the following lists as input - list1 = [5, 10, 15, 20, 25] list2 = [2, 5, 6, 7, 10, 15, 18, 20] list3 = [10, 20, 30, 40, 50, 60] We will find the common elements in three lists, and the output returned should be - [10, 20] Following are the ways to find common elements in three lists using Sets in Python - Using set.intersection() The set.intersection() method is used ... Read More

The objective is to break a list into chunks of a specific size (n), that is, splitting a list into sublists where each sublist contains n elements. For example, if the list is [12, 33, 11, 56, 44, 89, 23, 34, 12] and the chunk size is 3. Then the output has to be - [[12, 33, 11], [56, 44, 89], [23, 34, 12]]. To break a list into chunks of size n in Python, we use list comprehensions, Numpy library, slicing and others. Let's discuss all the approaches in detail with examples - Using List Comprehension List comprehension provides ... Read More

In this article, we will see how we can send email with attachments using Python. To send mail, we do not need any external library. There is a module called SMTPlib, which comes with Python. It uses SMTP (Simple Mail Transfer Protocol) to send the mail. It creates SMTP client session objects for mailing. SMTP needs valid source and destination email ids, and port numbers. The port number varies for different sites. As an example, for google the port is 587. At first we need to import the module to send mail. import smtplib Here we are also ... Read More