Strings & text
Format, split, join, parse, and clean text — everyday Python string patterns.
Find the Longest Word in a Sentence in Python
Splits a sentence into words and returns the longest one using the built-in max() function with len as the key.
def find_longest_word(sentence: str) -> str:
words = sentence.split()
if not words:
return ""
return max(words, key=len)
if __name__ == "__main__":
test_sentence = "The quick brown fox jumps over the lazy dog"
longest = find_longest_word(test_sentence)
print(f"Longest word: '{longest}'…How to Capitalize First Letter of Each Word in Python
Capitalizes the first letter of every word in a string using the built-in title() method.
def capitalize_words(text):
return text.title()
if __name__ == "__main__":
sample = "hello world from python"
result = capitalize_words(sample)
print(result)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 is Alphanumeric in Python
Uses the built-in str.isalnum() method to test whether a string contains only letters and numbers.
def is_alphanumeric(s: str) -> bool:
return s.isalnum()
if __name__ == "__main__":
test_cases = ["Hello123", "Hello World", "12345", "", "Hello@World", "Python3"]
for case in test_cases:
result = is_alphanumeric(case)
print(f"{case!r:15} -> {result}")How to Check if a String is Numeric in Python
This code provides a function to determine if a string represents a valid numeric value using Python's built-in float() conversion.
def is_numeric(s):
"""Check if a string represents a valid numeric value."""
try:
float(s)
return True
except (ValueError, TypeError):
return False
if __name__ == "__main__":
test_cases = ["123", "-45.67", "3.14e10", "0x1A", "abc", "12.5.6", " 42 ", ""]
for case in test_c…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 Pad a String with Zeros in Python
Pad a string to a fixed width by left-filling it with zeros using the built-in str.zfill method.
def pad_zeros(s, width):
return s.zfill(width)
if __name__ == "__main__":
print(repr(pad_zeros("42", 6)))
print(repr(pad_zeros("-7", 5)))
print(repr(pad_zeros("hello", 10)))
print(repr(pad_zeros("123", 3)))How to Partition a String on the First Delimiter in Python
Split a string into a tuple of (before, delimiter, after) at the first occurrence of a given delimiter, using a custom function or the built-in str.partition.
def partition_string(s, delimiter):
"""Split string into (before, delimiter, after) on the first occurrence."""
for i, ch in enumerate(s):
if ch == delimiter:
return s[:i], ch, s[i+1:]
return s, "", ""
if __name__ == "__main__":
# Single-character delimiter
s1 = "hello,world,h…How to Round Numbers with f-strings in Python
Round numbers directly inside f-string expressions using the built-in round() function for clean, readable output formatting.
def main():
# Values to format with expression-based rounding
price = 19.995
tax_rate = 0.0825
distance = 1234.56789
# Round inside the f-string expression using round()
print(f"Price rounded to cents: ${round(price, 2)}")
# Combine rounding with arithmetic inside the expression
total…How to Split a String by Comma in Python
Splits a comma-separated string into a list of trimmed items using Python's built-in split and a list comprehension.
def split_csv(line):
return [item.strip() for item in line.split(",")]
if __name__ == "__main__":
sample = "apple, banana, cherry, date"
result = split_csv(sample)
print(result)
print(f"Number of items: {len(result)}")How to Strip Whitespace in Python
This code demonstrates how to remove leading and trailing whitespace from a string using the built-in strip() method.
def strip_whitespace(text: str) -> str:
return text.strip()
if __name__ == "__main__":
sample = " Hello, world! "
result = strip_whitespace(sample)
print(f"Original: '{sample}'")
print(f"Stripped: '{result}'")How to Summarize Text Statistics in Python
This function returns basic statistics about a string, including character, word, and sentence counts, plus case and digit counts.
def summarize_text(text):
"""Return basic statistics about a string."""
words = text.split()
return {
"characters": len(text),
"words": len(words),
"sentences": text.count(".") + text.count("!") + text.count("?"),
"uppercase": sum(c.isupper() for c in text),
"lowerca…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…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.