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Python Regex: The 5 Exclusive Examples

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 Regular expressions (regex) are powerful tools for pattern matching and text manipulation in Python. Here are five Python regex examples with explanations: 01 Matching a Simple Pattern import re text = "Hello, World!" pattern = r"Hello" result = re.search(pattern, text) if result:     print("Pattern found:", result.group()) Output: Output: Pattern found: Hello This example searches for the pattern "Hello" in the text and prints it when found. 02 Matching Multiple Patterns import re text = "The quick brown fox jumps over the lazy dog." patterns = [r"fox", r"dog"] for pattern in patterns:     if re.search(pattern, text):         print(f"Pattern '{pattern}' found.") Output: Pattern 'fox' found. Pattern 'dog' found. It searches for both "fox" and "dog" patterns in the text and prints when they are found. 03 Matching Any Digit   import re text = "The price of the

How to Decode Python Exception Messages Like a Pro

While developing python programs, you might see exception messages from python. Here's an explanation to understand each part of the message.


Here're tips on how to understand python exceptions. You can find two kinds of exceptions. These are StandardError and StopIteration errors. Here is a chart that shows the types of python errors.



Exception message


Python exceptions class


Execptions

Python exceptions are basically three parts. Reading an error message produced by Python is not very difficult. The error type, the error description, and the traceback.


Understand the python exception message


The Error Type

There are so many in-built exception types in python. Here is the command to get all the exception types:


[x for x in dir(__builtins__) if 'Error' in x]


The Error description

The text message right after the error type gives us a description of what exactly the problem was. These descriptions are sometimes very accurate, sometimes not.

Sample error

Traceback (most recent call last): 
    File "load_tiles.py", line 32, in <module> wall = tiles['#'] 
KeyError: '#'

After the error type, there is only a # symbol, which means no clue even for Python.

The Traceback

The traceback contains accurate information where in the code an Exception happened. It contains the following:

  • A copy of the code is executed. Sometimes we spot the defect here immediately. Not this time.
  • The line number was executed when the error occurred. The defect must be in the line itself or in a line executed earlier.

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