Reference library

Comprehensions & generators

List/dict/set comprehensions, generator expressions, and lazy iteration.

3 matches

Drop n items then yield rest generator

A generator that skips the first n items of an iterable and then yields the remaining items one by one.

def drop(n, items):
    """Yield every item except the first n from items."""
    it = iter(items)
    for _ in range(n):
        next(it, None)  # skip first n items
    yield from it


if __name__ == "__main__":
    numbers = [10, 20, 30, 40, 50]
    result = list(drop(2, numbers))
    print(result)

11 0 Open

Comprehensions & generators easy

How to skip items until a condition is met in Python

Use itertools.dropwhile to skip leading elements while a predicate returns true, then yield the rest of the sequence unchanged.

itertools generators dropwhile

Python

def is_negative(x):
    return x < 0

numbers = [-3, -1, 0, 5, 2, -8, 7]
result = list(itertools.dropwhile(is_negative, numbers))
print(f"Original: {numbers}")
print(f"After dropwhile: {result}")

13 0 Open

Comprehensions & generators easy

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.

comprehensions generators normalization

Python

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…

13 0 Open

Browse by section

Each section groups closely related Python snippets.