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Automatically Detect Weak Passwords from Large Password Lists in Python
This Python script identifies weak passwords from a list by checking length, common patterns, sequential characters, and uniform characters, returning those that fail the security checks.
import re
COMMON_PASSWORDS_FILE = "common_passwords.txt"
def is_weak(password):
# Check length
if len(password) < 8:
return True
# Check for common patterns
if password.lower() in {"password", "123456", "qwerty", "letmein", "admin", "welcome"}:
return True
# Check for sequential c…Extract Email-Like Tokens from Text in Python
Uses a regular expression to find all email-like tokens in a string, returning them as a list with re.findall.
import re
def extract_email_like_tokens(text):
pattern = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b'
return re.findall(pattern, text)
if __name__ == "__main__":
sample_text = (
"Contact us at support@example.com or sales@company.co.uk. "
"Invalid: hello@world, user@.com, test@do…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 Palindrome in Python (Ignore Case and Spaces)
Check whether a string is a palindrome while ignoring case, spaces, and all non-alphanumeric characters using Python's filter and string reversal.
def is_palindrome(text: str) -> bool:
cleaned = ''.join(char.lower() for char in text if char.isalnum())
return cleaned == cleaned[::-1]
if __name__ == "__main__":
test_cases = [
"A man, a plan, a canal: Panama",
"race a car",
"Was it a car or a cat I saw?",
"hello",
…How to Detect PII in Documents Using Python
Use regex patterns to automatically detect emails, phone numbers, SSNs, and credit card numbers in text documents.
import re
from typing import List, Dict
def detect_pii(text: str) -> Dict[str, List[str]]:
patterns = {
"email": r"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}",
"phone": r"\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}",
"ssn": r"\b\d{3}-\d{2}-\d{4}\b",
"credit_card": r"\b\d{4}[- ]?\d{4}[-…How to Extract Digits Only from a String in Python
This code uses a regular expression to remove all non-digit characters from a mixed string, returning only the digits.
import re
def extract_digits(text):
"""Return only the digits from the given text as a string."""
return re.sub(r'\D', '', text)
if __name__ == "__main__":
mixed = "abc123def456!@#789"
result = extract_digits(mixed)
print(result)How to Highlight Search Terms in Python Text
Highlights all case-insensitive occurrences of a search term in a string by wrapping them in markers.
def highlight_search_term(text: str, term: str) -> str:
"""Highlight all occurrences of term in text using terminal-style markers."""
if not term:
return text
term_lower = term.lower()
result = []
i = 0
while i < len(text):
# Check if the term starts at position i (case-insens…How to Remove Duplicate Adjacent Spaces in Python
This Python function collapses any sequence of two or more adjacent spaces into a single space, preserving all other characters.
def remove_duplicate_adjacent_spaces(text):
"""Replace sequences of 2+ spaces with a single space."""
result = []
prev_was_space = False
for char in text:
if char == " ":
if not prev_was_space:
result.append(char)
prev_was_space = True
else:
…How to Remove HTML Tags in Python with Regex
Strips all HTML tags from a string using a regular expression and cleans extra whitespace.
import re
def remove_html_tags(text: str) -> str:
"""Remove all HTML tags from the given text using regex."""
# Remove opening and closing tags
clean = re.sub(r'<[^>]+>', '', text)
# Remove any extra whitespace left behind
clean = re.sub(r'\s+', ' ', clean).strip()
return clean
if __name__ ==…How to Sort Text Alphabetically in Python
Sort words or lines alphabetically with case-insensitive ordering while preserving original casing.
def sort_words(text):
"""Sort words alphabetically (case-insensitive), preserving case."""
words = text.split()
return sorted(words, key=str.lower)
def sort_lines(text):
"""Sort lines alphabetically (case-insensitive), preserving case."""
lines = [line for line in text.splitlines() if line.strip(…How to Sort Text in Python with a Simple Helper Function
A compact helper function that sorts a list of strings or splits a string into words and sorts them alphabetically, with optional reverse ordering.
def sort_text(data, reverse=False):
"""
Sort a list of strings (or a single string split into words) alphabetically.
"""
if isinstance(data, str):
words = data.split()
else:
words = [str(item) for item in data]
return sorted(words, reverse=reverse)
if __name__ == "__main__":
…How to remove punctuation from a string in Python
Remove all punctuation characters from a string using the str.translate method and string.punctuation from the standard library.
import string
def remove_punctuation(text: str) -> str:
return text.translate(str.maketrans("", "", string.punctuation))
if __name__ == "__main__":
sample = "Hello, world! It's a test... (with punctuation) - done?"
cleaned = remove_punctuation(sample)
print(f"Original: {sample}")
print(f"Cleaned:…Check if List is Sorted Ascending in Python
Verify that a list is sorted in ascending order using the all() function and a generator expression.
def is_sorted_ascending(lst):
return all(lst[i] <= lst[i + 1] for i in range(len(lst) - 1))
if __name__ == "__main__":
test_lists = [
[1, 2, 3, 4, 5],
[1, 3, 2, 4, 5],
[5, 4, 3, 2, 1],
[1, 1, 2, 2, 3],
[10],
[]
]
for lst in test_lists:
print(f"{l…Find All Occurrences of an Item in a Python List
Loop through a list with enumerate() to collect the index of every match for a target value.
def find_all(data, target):
"""Return indices of every occurrence of target in a list."""
indices = []
for index, item in enumerate(data):
if item == target:
indices.append(index)
return indices
if __name__ == "__main__":
sample = [10, 20, 30, 20, 40, 20, 50]
target_value …Find Local Minima (Valleys) in a Numeric List in Python
This code finds indices of all local minima (valleys) in a numeric list, including edge cases, using a simple loop that compares each element with its neighbors.
def find_local_minima(numbers):
"""Find indices of local minima (valleys) in a numeric list.
A value is a local minimum if it's less than or equal to its neighbors.
Edge elements are considered minima if they're less than or equal to their single neighbor.
"""
if not numbers:
return []…Find Maximum Value in a List of Numbers in Python
Iterate through a list with a for loop to manually find and return the maximum numeric value.
def find_max(numbers):
"""Return the maximum value in a list of numbers."""
if not numbers:
return None
max_value = numbers[0]
for num in numbers[1:]:
if num > max_value:
max_value = num
return max_value
if __name__ == "__main__":
sample_list = [3, 7, 2, 15, 9, 11]
…How to Build a Running Maximum List in Python
Compute a list where each element is the maximum of all numbers seen so far from an input list.
def running_maximum(numbers):
result = []
current_max = float('-inf')
for num in numbers:
if num > current_max:
current_max = num
result.append(current_max)
return result
if __name__ == "__main__":
numbers = [3, 1, 4, 1, 5, 9, 2, 6]
max_list = running_maximum(number…How to Calculate a Cumulative Sum in Python
Build a new list where each element equals the running total of all numbers up to that index in the original list.
numbers = [1, 2, 3, 4, 5]
cumulative_sum = []
running_total = 0
for num in numbers:
running_total += num
cumulative_sum.append(running_total)
print(cumulative_sum)How to Calculate the Sum of List Elements in Python
Iterates over a list with a for loop, accumulates each number into a total variable, and returns the sum of all elements.
def sum_list_elements(numbers):
"""Return the sum of all elements in a list."""
total = 0
for num in numbers:
total += num
return total
if __name__ == "__main__":
sample_list = [1, 2, 3, 4, 5]
result = sum_list_elements(sample_list)
print(f"The sum of {sample_list} is {result}")How to Check if a List is Sorted in Descending Order in Python
This code defines a function that returns True if a given list is sorted in descending order, using a generator expression with all() to compare each adjacent pair.
def is_descending(lst):
"""Return True if list is sorted in descending order."""
return all(lst[i] >= lst[i + 1] for i in range(len(lst) - 1))
if __name__ == "__main__":
test_cases = [
[5, 4, 3, 2, 1],
[3, 3, 2, 1],
[1, 2, 3],
[10, 8, 9],
[]
]
for case in …How to Convert Data Types in Python Lists
Convert a mixed list of values to integers, floats, or strings based on their content, with graceful fallback for unparseable strings.
def convert_data(data):
"""Convert a mixed list of values to strings, ints, and floats."""
result = []
for item in data:
if isinstance(item, (int, float)):
result.append(str(item))
elif isinstance(item, str):
try:
if '.' in item:
r…How to Find Local Maxima in a Python List
Return the indices of all local maxima in a numeric list, where a peak is an element greater than both its immediate neighbors.
def find_peaks(numbers):
"""
Return the indices of local maxima in a numeric list.
A local maximum is an element greater than both its neighbors.
"""
if len(numbers) < 3:
return []
peaks = []
for i in range(1, len(numbers) - 1):
if numbers[i] > numbers[i - 1] and number…How to Find the Third Smallest Element in a Python List
Find the third smallest distinct value in a Python list by sorting unique elements and returning the third index.
def find_third_smallest(numbers):
if len(numbers) < 3:
return None
unique_sorted = sorted(set(numbers))
if len(unique_sorted) < 3:
return None
return unique_sorted[2]
if __name__ == "__main__":
sample = [5, 2, 8, 2, 9, 1, 7, 3]
result = find_third_smallest(sampl…How to Sort a List of Dictionaries by a Key in Python
Sort a list of dictionaries by a specified key field, optionally in descending order, using Python's built-in sorted() function.
def sort_dicts_by_key(data, key, reverse=False):
return sorted(data, key=lambda item: item.get(key), reverse=reverse)
if __name__ == "__main__":
people = [
{"name": "Alice", "age": 30},
{"name": "Bob", "age": 25},
{"name": "Charlie", "age": 35},
]
sorted_by_age = sort_dicts_b…Browse by section
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