Skip to main content Brad's PyNotes

Built-in Functions: Python's Essential Toolkit

TL;DR

Python’s built-in functions like map(), filter(), zip(), and enumerate() provide powerful, memory-efficient ways to process data without explicit loops.

Interesting!

The any() and all() functions can short-circuit evaluation - any() returns True as soon as it finds one truthy value, making them incredibly efficient for large datasets.

Essential Functions

python code snippet start

# map() - Transform every element
numbers = list(map(int, ['1', '2', '3']))
squares = list(map(lambda x: x**2, range(5)))

# filter() - Select elements
evens = list(filter(lambda x: x % 2 == 0, range(10)))

# zip() - Combine iterables
names = ['Alice', 'Bob']
ages = [25, 30]
combined = list(zip(names, ages))  # [('Alice', 25), ('Bob', 30)]

# enumerate() - Add indices
for i, item in enumerate(['a', 'b', 'c']):
    print(f"{i}: {item}")

python code snippet end

Logic and Aggregation

python code snippet start

# any() and all()
scores = [85, 92, 78, 96]
has_high = any(score > 90 for score in scores)  # True
all_passing = all(score >= 70 for score in scores)  # True

# min(), max(), sum()
print(min(scores))  # 78
print(max(scores, key=lambda x: x))  # 96
print(sum(scores))  # 351

python code snippet end

Python’s built-in functions form the foundation of elegant, efficient programming.

Built-in functions work seamlessly with itertools and functools for powerful functional programming patterns. These functions embody Zen of Python principles and integrate naturally with collections containers for data processing. The enumerate() function deserves special attention for adding indices to loops.

Reference: Python Built-in Functions Documentation