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Basic Regular Expressions and Metacharacters in Python

Introduction
Setting Up Your Python Environment
Installing Python and PyCharm IDE Creating and Running Your First Python Program
Python Data Types
Numeric Types String Types Boolean Types None Type
Operators and Expressions
Arithmetic Operators Comparison Operators Logical Operators Bitwise Operators Assignment Operators Operator Precedence
Control Flow Statements
Conditional Statements Loops Break and Continue Statements Exception Handling
Functions and Modules
Defining and Calling Functions Function Arguments and Return Values Lambda Functions Modules and Packages
Python Data Structures
Lists Tuples Dictionaries Sets Arrays
ObjectOriented Programming in Python
Classes and Objects Attributes and Methods Inheritance and Polymorphism Abstract Classes and Interfaces
File Handling
Opening and Closing Files Reading and Writing Text Files Reading and Writing Binary Files CSV Files
Regular Expressions
Basic Regular Expressions and Metacharacters Anchors and Quantifiers Grouping and Capturing Lookarounds
Datetime and Timezones
Date and Time Objects Date and Time Formatting Timezone and Daylight Saving Time Handling
Debugging and Testing
Debugging Techniques Debugging Tools in PyCharm Unit Testing with PyTest
Web Scraping with Python
Requesting Data with urllib Parsing HTML with Beautiful Soup Extracting and Storing Data
Database Handling with Python
Connecting to Databases Performing CRUD Operations Database Access with ORM (ObjectRelational Mapping)
Introduction to Data Science with Python
NumPy Pandas Matplotlib ScikitLearn
GUI Programming with Python
Creating GUI Applications GUI Toolkits (Tkinter, PyQt, wxWidgets)
Network Programming with Python
Socket Programming Creating and Running a Simple Web Server Connecting to APIs
Best Practices and Tips
Python Coding Standards Code Organization Writing Efficient Code Tips and Tricks for Python Development
Conclusion and Next Steps.

Basic Regular Expressions and Metacharacters

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Regular expressions (regex) are a powerful tool for manipulating text. They are a sequence of characters that form a search pattern, which can be used to search for specific patterns of characters within a string or a document.

In Python, you can use regular expressions by importing the re module. This module provides a set of functions that allow you to search, match, and manipulate strings using regular expressions.

Basic Regular Expressions and Metacharacters are building blocks of regular expressions.

Some of the basic regex metacharacters include:
  1. Dot (.): This metacharacter matches any character except newline.
  1. Caret (^): This metacharacter matches the beginning of the string.
  1. Dollar ($): This metacharacter matches the end of the string.
  1. Square brackets ([]): This metacharacter matches any one of the characters in the brackets.
  1. Pipe (|): This metacharacter matches either the expression before or after it.
  1. Asterisk (*): This metacharacter matches zero or more occurrences of the preceding expression.
  1. Plus (+): This metacharacter matches one or more occurrences of the preceding expression.
  1. Question mark (?): This metacharacter matches zero or one occurrence of the preceding expression.

Using these basic regex metacharacters, you can form complex patterns to match and manipulate any text. For example, the pattern "ca[eo]t" will match any string that has "cat" or "cot" in it.

Learning regular expressions is an essential skill for any Python programmer who needs to manipulate text data.

March 25, 2023

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