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Extract Data from Strings in Python: Beginner's Guide
A beginner-friendly helper that splits a comma-separated string into a list, shows word count, and extracts the first and last words using Python's split() and join() methods.
text = "python,string,extract,beginner"
words = text.split(",")
print("Full text:", text)
print("Word count:", len(words))
print("First word:", words[0])
print("Last word:", words[-1])
joined = " | ".join(words)
print("Joined with separator:", joined)How to Build a Basic Text Processor in Python
Split text into sentences, count words, find the longest word, and convert text to uppercase — all with pure Python string methods.
text = """The quick brown fox jumps over the lazy dog.
Python is a powerful programming language.
Keep practicing every single day!"""
sentences = text.split(". ")
word_count = 0
longest_word = ""
for sentence in sentences:
words = sentence.split()
word_count += len(words)
for word in words:
clea…How to Check and Manipulate Strings in Python
Demonstrates core string inspection and transformation methods like case conversion, trimming, splitting, and membership checks on a sample string.
text = " Hello, Python Learners! "
print(f"Original: '{text}'")
print(f"Lowercase: '{text.lower()}'")
print(f"Uppercase: '{text.upper()}'")
print(f"Title case: '{text.title()}'")
print(f"Stripped: '{text.strip()}'")
print(f"Length: {len(text)}")
print(f"Replace: '{text.replace('Python', 'Programming')}'")
print(f"S…How to Check if a String Ends with a File Extension in Python
This code checks whether a filename ends with any of a list of file extensions, handling case insensitivity.
def ends_with_extension(filename, extensions):
"""Check if a filename ends with any of the given extensions."""
lower_name = filename.lower()
return any(lower_name.endswith(ext.lower()) for ext in extensions)
if __name__ == "__main__":
# Test cases
test_files = ["report.pdf", "image.PNG", "script.…How to Check if a String Starts With a Prefix Case-Insensitively in Python
This code defines a function that checks if a string starts with a given prefix, ignoring case, using the lower() method.
def starts_with_case_insensitive(text, prefix):
"""Check if a string starts with a given prefix, ignoring case."""
return text.lower().startswith(prefix.lower())
if __name__ == "__main__":
test_strings = [
("Hello World", "hello"),
("Python Programming", "PYTHON"),
("Data Science"…How to Convert and Process Text in Python
This code cleans, converts, splits, joins, counts, replaces, reverses, and finds substrings in a text string using Python's standard string methods.
text = " hello world, python is fun! "
# Clean up whitespace
cleaned = text.strip()
# Convert to title case
titled = cleaned.title()
# Split into words
words = cleaned.split()
# Join with hyphens
hyphenated = "-".join(words)
# Count occurrences of a letter
letter_count = cleaned.count("o")
# Replace a word
rep…How to Count Words in a String in Python
Split a paragraph on whitespace and return the number of words using Python's built-in string methods.
def count_words(paragraph: str) -> int:
words = paragraph.split()
return len(words)
if __name__ == "__main__":
paragraph = "The quick brown fox jumps over the lazy dog."
result = count_words(paragraph)
print(f"Word count: {result}")How to Generate Initials from a Full Name in Python
Extract and uppercase the first letter of each word in a full name to produce initials using standard string methods.
def generate_initials(full_name):
parts = full_name.strip().split()
initials = ''.join(part[0].upper() for part in parts if part)
return initials
if __name__ == "__main__":
name = "john f. kennedy"
print(generate_initials(name))How to Process Lines of Text in Python
Strip whitespace, split a multi-line string, count words per line, and print structured summaries using basic string methods and loops.
text = """ Python is great!
Coding is fun.
Python skills help you grow. """
lines = text.strip().splitlines()
line_count = len(lines)
processed = []
for line in lines:
stripped = line.strip()
word_count = len(stripped.split())
processed.append({
"original": line,
"stripped": stripp…Text Processor Functions for Beginners in Python
Demonstrates simple text-processing utilities: word counting, word reversal, whitespace normalization, and lowercase conversion using basic string methods.
def count_words(text):
"""Return the number of words in a string."""
return len(text.split())
def reverse_words(text):
"""Return the text with words in reverse order."""
return ' '.join(text.split()[::-1])
def remove_extra_spaces(text):
"""Return text with extra whitespace collapsed to a single s…How to Parse Bullet Points in Python
Extract bullet point items from raw text by splitting lines and filtering those that start with '- ' or '* '.
def parse_bullet_points(text):
"""Extract bullet point items from raw text."""
lines = text.splitlines()
items = []
for line in lines:
stripped = line.strip()
if stripped.startswith("- ") or stripped.startswith("* "):
item = stripped[2:]
if item:
…How to Validate Text Against Forbidden Words in Python
Checks whether a given text contains any forbidden words and returns a tuple with validity and offending words.
def validate_text(text, forbidden_words):
"""
Checks that text does not contain any forbidden words.
Returns (is_valid, offending_words) tuple.
"""
words = text.lower().split()
found = [word for word in words if word in forbidden_words]
return len(found) == 0, found
if __name__ == "__main…How to Create an Iterator Class with Dunder Methods in Python
A minimal Counter class implementing __iter__ and __next__ to act as a self-iterating iterator, yielding numbers from start to end-1.
class Counter:
def __init__(self, start=0, end=5):
self.current = start
self.end = end
def __iter__(self):
return self
def __next__(self):
if self.current >= self.end:
raise StopIteration
value = self.current
self.current += 1
return val…How to Emit Deprecation Warnings in Python
Use the warnings module to mark legacy classes and methods as deprecated, letting users know to switch to newer APIs.
import warnings
class OldAPI:
def __init__(self):
warnings.warn(
"OldAPI is deprecated; use NewAPI instead.",
DeprecationWarning,
stacklevel=2,
)
self.data = []
def add(self, item):
warnings.warn(
"OldAPI.add() is deprecated; us…Build a Case-Insensitive Dict with a Wrapper Class in Python
Create a custom dict subclass that treats keys as case-insensitive by normalizing them to lowercase, with a full set of common dict methods.
class CaseInsensitiveDict:
def __init__(self, data=None):
self._data = {}
if data:
self.update(data)
def __setitem__(self, key, value):
self._data[str(key).lower()] = value
def __getitem__(self, key):
return self._data[str(key).lower()]
def __delitem__(sel…Graph Class with Adjacency Dict in Python
Build an undirected graph class using a dictionary of adjacency lists with methods to add vertices, edges, remove edges, and query neighbors.
class Graph:
def __init__(self):
self.adjacency = {}
def add_vertex(self, vertex):
if vertex not in self.adjacency:
self.adjacency[vertex] = []
def add_edge(self, u, v):
self.add_vertex(u)
self.add_vertex(v)
self.adjacency[u].append(v)
self.adja…How to Build a Fluent Interface with the Builder Pattern in Python
Learn to implement a fluent builder pattern in Python by chaining methods that return self, enabling readable object construction.
class Pizza:
def __init__(self):
self.size = None
self.toppings = []
self.crust = None
def set_size(self, size):
self.size = size
return self
def add_topping(self, topping):
self.toppings.append(topping)
return self
def set_crust(self, crust):
…How to Build a Linked List Node Class in Python
Create a Node class and a LinkedList class with insert, remove, and display methods to manage a singly linked list.
class Node:
def __init__(self, data):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def insert(self, data):
new_node = Node(data)
if not self.head:
self.head = new_node
else:
current = self.…How to Count Items in a Python Class
A beginner-friendly Inventory class that stores item quantities in a dictionary and provides add, remove, count, and summary methods.
class Inventory:
def __init__(self):
self.items = {}
def add(self, item, quantity=1):
self.items[item] = self.items.get(item, 0) + quantity
def remove(self, item, quantity=1):
if item not in self.items:
raise ValueError(f"{item} not in inventory")
self.items[it…How to Create Static Methods in a Python Class
Shows how to define and call static methods inside a class using @staticmethod, with utility functions that don't need instance or class state.
class MathUtils:
"""Utility class demonstrating static methods."""
@staticmethod
def add(a, b):
"""Return the sum of two numbers."""
return a + b
@staticmethod
def multiply(a, b):
"""Return the product of two numbers."""
return a * b
@staticmethod
…How to Create a Data Helper Class in Python with OOP
A complete OOP example with User, Post, and Blog classes that manage data relationships and provide clear helper methods.
class User:
def __init__(self, name, email):
self.name = name
self.email = email
self.posts = []
def create_post(self, title, content):
post = Post(title, content, self)
self.posts.append(post)
return post
def get_post_count(self):
return len(self.p…How to Create an Iterable Class with __iter__ and __next__ in Python
Build custom iterable classes in Python by implementing the __iter__ and __next__ dunder methods to yield items on demand.
class EvenNumbers:
def __init__(self, limit):
self.limit = limit
self.current = 0
def __iter__(self):
return self
def __next__(self):
if self.current >= self.limit:
raise StopIteration
result = self.current
self.current += 2
return resul…How to Implement Iterator Protocol on a Custom Class in Python
Create a custom iterable class by defining the __iter__ and __next__ methods, enabling use in for loops and list conversions.
class Countdown:
"""Iterator that counts down from start to 0."""
def __init__(self, start):
self.start = start
self.current = start
def __iter__(self):
return self
def __next__(self):
if self.current < 0:
raise StopIteration
value = self.current
…How to Implement Rich Comparison Ordering in Python Classes
This code demonstrates how to implement rich comparison operators (like <, <=, >, >=, ==, !=) in a Python class by defining __lt__ and __eq__, enabling sorting and ordering of custom objects.
class Task:
def __init__(self, priority, name):
self.priority = priority
self.name = name
def __lt__(self, other):
if not isinstance(other, Task):
return NotImplemented
return self.priority < other.priority
def __eq__(self, other):
if not isinstance(oth…Browse by section
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