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Comprehensions & generators

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

5 matches

How to Filter Data with Predicates in Python

This helper filters a list with a predicate using a list comprehension, plus a lazy generator version that yields matches one by one.

filtering comprehensions generators

Python

def filter_data(data, predicate):
    """Return a list containing only items that pass the predicate."""
    return [item for item in data if predicate(item)]


def filter_data_lazy(data, predicate):
    """Generator version: yields items that pass the predicate one by one."""
    for item in data:
        if predicat…

16 0 Open

Comprehensions & generators easy

How to Group Data in Python with defaultdict and Comprehensions

Group a list of items by a computed key using a defaultdict-based generator helper and an alternative dictionary comprehension approach.

grouping defaultdict comprehensions

Python

from collections import defaultdict

def group_by(data, key_func):
    """Group items in data by the value returned by key_func."""
    result = defaultdict(list)
    for item in data:
        result[key_func(item)].append(item)
    return dict(result)

def group_by_comprehension(data, key_func):
    """Same grouping …

15 0 Open

Comprehensions & generators easy

How to Use Comprehensions and Generators to Check Data in Python

A beginner-friendly helper that filters numeric values, computes squares and cubes with comprehensions and a generator, and returns a summary dictionary.

comprehensions generators data-checking

Python

def check_data(iterable):
    """Return a summary of numeric data using comprehensions and a generator."""
    values = [item for item in iterable if isinstance(item, (int, float))]
    squares = [x ** 2 for x in values if x > 0]
    cubes = (x ** 3 for x in values if x > 0)
    cube_list = list(cubes)
    return {
  …

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Comprehensions & generators easy

How to Use List Comprehensions and Generators to Format Data in Python

A beginner-friendly helper that formats dictionaries into strings using a list comprehension and generates squared numbers lazily with a generator.

list comprehension generators formatting

Python

def format_data(items):
    """Format a list of dictionaries into readable strings."""
    formatted = [
        f"{item.get('name', 'Unknown')}: {item.get('value', 0)} units"
        for item in items
        if item.get('value', 0) > 0
    ]
    return formatted if formatted else ["No positive values found"]


def g…

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Comprehensions & generators easy

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.

comprehensions generators data-helpers

Python

# 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…

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