Comprehensions & generators
List/dict/set comprehensions, generator expressions, and lazy iteration.
Chunk an Iterable into Batches with a Generator in Python
Yield fixed-size batches from any iterable lazily using itertools.islice inside a generator function.
from itertools import islice
def chunked(iterable, size):
iterator = iter(iterable)
while True:
batch = list(islice(iterator, size))
if not batch:
break
yield batch
if __name__ == "__main__":
data = range(10)
for batch in chunked(data, 3):
print(batch)Generate Data with Python Comprehensions and Generators
Shows list, dict compregensions and generator expressions plus a Fibonacci generator to produce data lazily.
# Data generation helpers using comprehensions and generators
from itertools import islice
def fibonacci(limit):
"""Generate Fibonacci numbers up to a limit."""
a, b = 0, 1
while a <= limit:
yield a
a, b = b, a + b
def main():
# List comprehension: squares of even numbers
square…How to Create an Infinite Arithmetic Sequence Generator in Python
Build a memory-efficient generator that yields an infinite arithmetic progression and extract the first N values with list comprehension.
"""Count generator infinite arithmetic progression"""
def arithmetic_counter(start=0, step=1):
"""Generate an infinite arithmetic sequence."""
current = start
while True:
yield current
current += step
if __name__ == "__main__":
counter = arithmetic_counter(1, 3)
result = [next(c…How to Generate Fibonacci Numbers in Python Without Recursion
Build an efficient infinite Fibonacci sequence using a generator function with O(1) memory and no recursion overhead.
def fib(n):
a, b = 0, 1
for _ in range(n):
yield a
a, b = b, a + b
if __name__ == "__main__":
count = 10
result = list(fib(count))
print(result)How to Split Data into Chunks and Use Generators in Python
Split a list into fixed-size chunks with a list comprehension and square even numbers lazily with a generator expression.
def split_numbers(data, chunk_size):
return [data[i:i + chunk_size] for i in range(0, len(data), chunk_size)]
def square_even_numbers(numbers):
return (n ** 2 for n in numbers if n % 2 == 0)
if __name__ == "__main__":
sample_data = list(range(1, 21))
chunks = split_numbers(sample_data, 5)
print…Normalize Data in Python with Comprehensions and Generators
Clean a list by dropping None values with a comprehension, then min-max normalize it using a lazy generator expression — a beginner-friendly data preparation pattern.
import statistics
# Sample raw data including missing and outlier-ish values
raw = [22, 18, None, 25, 30, 19, 22, 17, None, 28, 24]
# Clean the data: drop None values using a list comprehension
clean = [x for x in raw if x is not None]
# Normalize using min-max scaling with a generator expression
min_val = min(clea…Python Comprehensions and Generators for Beginners
Learn list, dict, and set comprehensions plus generator expressions and generator functions with clear, runnable examples.
# Demonstrates list comprehensions, dict comprehensions, set comprehensions, and generators
def demonstrate_comprehensions():
# List comprehension: squares of even numbers
numbers = range(1, 11)
even_squares = [n ** 2 for n in numbers if n % 2 == 0]
# Dict comprehension: number to its factorial
…Take n items from an infinite Python generator
Uses itertools.islice to lazily take exactly n items from an infinite generator without exhausting it.
from itertools import islice
def count_up_from(start=0):
n = start
while True:
yield n
n += 1
def take_n(generator, count):
return list(islice(generator, count))
if __name__ == "__main__":
gen = count_up_from(10)
result = take_n(gen, 5)
print(result)Write Data Helpers with Comprehensions and Generators in Python
Demonstrates list, dict, and set comprehensions plus generator expressions and generator functions for building concise data helpers.
# Basic comprehensions and generators demo
# List comprehension: squares of evens
squares = [x * x for x in range(10) if x % 2 == 0]
print("List comp:", squares)
# Dictionary comprehension: char -> count
text = "hello"
char_counts = {c: text.count(c) for c in set(text)}
print("Dict comp:", char_counts)
# Set compre…Browse by section
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Comprehensions & generators — Python code examples
What you will find here
This page collects comprehensions & generators 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.
Samples vs tutorials and challenges
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.