Strings & text
Format, split, join, parse, and clean text — everyday Python string patterns.
How to Swap Case of Every Character in Python
Swap uppercase to lowercase and lowercase to uppercase for every character in a string using Python's built-in swapcase() method.
def swap_case(text):
"""
Swap uppercase to lowercase and lowercase to uppercase
for every character in the given string.
"""
return text.swapcase()
if __name__ == "__main__":
sample = "Hello World! Python3.9"
result = swap_case(sample)
print(f"Input: {sample}")
print(f"Output: {r…How to Transform Text in Python with a Helper Function
Build a simple Python helper to strip extra whitespace and convert text to upper, lower, or title case.
def transform_text(text, upper=False, lower=False, strip_whitespace=False, title_case=False):
"""Apply common string transformations for beginners."""
result = text
if strip_whitespace:
result = " ".join(result.split())
if upper and lower:
raise ValueError("Cannot apply both upper and…How to Translate Characters in a String with str.maketrans in Python
Build and apply character translation tables with str.maketrans and str.translate to replace, delete, or remap letters in a Python string.
def translate_demo():
# Build a translation table: a→1, e→2, i→3, o→4, u→5
table = str.maketrans("aeiou", "12345")
text = "Hello, Python world! Keep coding, friend."
translated = text.translate(table)
print(f"Original: {text}")
print(f"Translated: {translated}")
# Example wit…How to Truncate a String with Ellipsis in Python
A function that shortens text to a maximum length and appends an ellipsis when truncation occurs, handling edge cases.
def truncate_with_ellipsis(text: str, max_length: int) -> str:
"""Truncate text to max_length, appending ellipsis if truncated."""
if len(text) <= max_length:
return text
if max_length <= 3:
return text[:max_length]
return text[: max_length - 3] + "..."
if __name__ == "__main__":
t…How to Unescape HTML Entities in Python
Convert HTML entities like & and < back to their literal characters using the standard library html module.
import html
def unescape_html_entities(text: str) -> str:
"""Convert HTML entities like & to their character equivalents."""
return html.unescape(text)
if __name__ == "__main__":
sample = "Tom & Jerry <cartoon> "classic" 'fun' © 2024"
result = unescape_html_enti…How to Use Template Strings for Substitution in Python
This code shows how to use Python's Template class for safe string substitution, replacing placeholders like $name with actual values.
from string import Template
def format_user_message(name, role, company):
template = Template("Hello $name! We are glad to have you as our $role at $company.")
return template.substitute(name=name, role=role, company=company)
if __name__ == "__main__":
result = format_user_message("Alice", "Python Develo…How to Validate Text Input in Python: A Simple Text Processor
A Python function that validates a text string by trimming whitespace, then returns a dictionary with character, word, and sentence counts.
def validate_text(text: str) -> dict:
"""Analyze a text string and return basic validation statistics."""
stripped = text.strip()
if not stripped:
return {
"valid": False,
"reason": "Text is empty or only whitespace",
"characters": 0,
"words": 0,
…How to Validate Text Strings in Python
Validate strings with a reusable helper that checks type, length limits, and empty string handling.
def is_valid_text(value, min_length=1, max_length=None, allow_empty=False):
"""
Validate if a value is a string and meets length requirements.
Args:
value: The value to validate
min_length: Minimum allowed length (default 1)
max_length: Maximum allowed length (None = no limit)
…How to build a text helper in Python for beginners
This code provides easy-to-use functions for cleaning text, removing punctuation, counting word frequencies, and summarizing strings — perfect for beginners.
def clean_text(text: str) -> str:
"""Clean and normalize a text string."""
text = text.strip()
text = text.replace(" ", " ")
text = text.capitalize()
text = text.replace(".", ".")
return text
def remove_punctuation(text: str) -> str:
"""Remove common punctuation marks from a string."""
…How to parse key=value pairs in Python
Parse a single line of key=value pairs separated by a delimiter into a Python dictionary.
def parse_key_value_pairs(line: str, delimiter: str = "&") -> dict:
"""Parse a single line of key=value pairs into a dictionary."""
pairs = {}
for token in line.split(delimiter):
if not token.strip():
continue
key, _, value = token.partition("=")
pairs[key.strip()] = val…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:…How to wrap long text to a specified width in Python
Uses Python's textwrap.fill to wrap a long string to a specified width at word boundaries, preserving readability in console output or logs.
import textwrap
text = """This is a long piece of text that definitely exceeds the width limit
if we try to print it on a single line without any wrapping applied."""
wrapped = textwrap.fill(text, width=40)
print(wrapped)Normalize unicode accents to ASCII in Python
This code converts accented Unicode characters to ASCII equivalents using the standard library's unicodedata module.
import unicodedata
def normalize_accents(text: str) -> str:
"""Convert accented unicode characters to ASCII equivalents."""
decomposed = unicodedata.normalize('NFD', text)
ascii_text = ''.join(
char for char in decomposed
if unicodedata.category(char) != 'Mn'
)
return unicodedata.n…Python String Helper Functions for Beginners
A set of beginner-friendly Python functions that count words, reverse text, convert to title case, strip punctuation, and compute character frequency from a string.
def count_words(text):
"""Count the number of words in a string."""
return len(text.split())
def reverse_text(text):
"""Reverse the entire string."""
return text[::-1]
def title_case(text):
"""Capitalize the first letter of each word."""
return text.title()
def remove_punctuation(text):
…Python String isalpha() Method: Check if String is Alphabetic
This code defines a function that uses Python's str.isalpha() method to determine if a string contains only alphabetic characters, with a demonstration on several test strings.
def is_alphabetic(s):
return s.isalpha()
if __name__ == "__main__":
test_strings = ["Hello", "Hello123", "World!", "Python", ""]
for s in test_strings:
print(f"{s!r}: {is_alphabetic(s)}")Python: Replace Spaces with Hyphens for Slug
Transform a string by stripping surrounding whitespace and replacing each space with a hyphen to create a simple slug.
def slugify(text):
return text.strip().replace(" ", "-")
if __name__ == "__main__":
title = "Hello World Python Example"
result = slugify(title)
print(result)Remove Substring Occurrences Case-Insensitively in Python
This code removes every case-insensitive occurrence of a given substring from a text string using a simple looping approach.
def remove_occurrences_ci(text: str, substring: str) -> str:
"""Remove all case-insensitive occurrences of substring from text."""
if not substring:
return text
result = []
i = 0
lower_text = text.lower()
lower_sub = substring.lower()
sub_len = len(substring)
while i <…Repeat a string n times with a separator in Python
Repeats a string a given number of times, joining the repetitions with an optional separator, with a guard for non-positive counts.
def repeat_string_with_separator(s, n, sep=''):
"""
Repeats a string n times, joining with a separator.
Args:
s (str): The string to repeat.
n (int): Number of repetitions.
sep (str): Separator between repetitions (default: '').
Returns:
str: The repeated strin…Reverse Words in a Sentence While Keeping Punctuation in Python
Reverses the order of words in a sentence while leaving punctuation and spaces in their original positions using Python's re module.
def reverse_words_preserving_punctuation(sentence: str) -> str:
import re
# Split into words and punctuation tokens
tokens = re.findall(r'\w+|[^\w\s]|\s+', sentence)
words = [t for t in tokens if re.fullmatch(r'\w+', t)]
words.reverse()
result_parts = []
word_index = 0
for token in toke…String helpers in Python: stats, reverse, and remove vowels
Three beginner-friendly Python functions compute text statistics, reverse word order, and strip vowels from a string.
def text_stats(text: str) -> dict:
"""Return basic statistics for a given text string."""
words = text.split()
return {
"characters": len(text),
"words": len(words),
"sentences": text.count(".") + text.count("!") + text.count("?"),
"uppercase": sum(1 for c in text if c.isupp…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…Validate email format with regex in Python
A Python function using a regex pattern to validate simple email formats, returning True or False for each input.
import re
def is_valid_email(email):
pattern = r'^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$'
return bool(re.match(pattern, email))
if __name__ == "__main__":
test_emails = [
"user@example.com",
"first.last@sub.domain.org",
"invalid-email",
"user@.com",
"user@…Browse by section
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Strings & text — Python code examples
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This page collects strings & text snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.