How Can I Efficiently Iterate Over a List in Chunks Using Python?

Iterating over a List in Chunks: A Pythonic Perspective

In Python, the task of iterating over a list in chunks can be accomplished in various ways. One common approach involves using a loop to incrementally access elements at specific intervals:

for i in range(0, len(ints), 4):
    # dummy op for example code
    foo += ints[i] * ints[i + 1] + ints[i + 2] * ints[i + 3]

This method, while functional, can introduce unnecessary complexity and "C-think" into your Python code. A more Pythonic approach involves leveraging the built-in range() function and slicing:

def chunker(seq, size):
    return (seq[pos:pos + size] for pos in range(0, len(seq), size))

The chunker function creates a generator expression that iterates through the sequence, yielding chunks of the desired size starting from various positions. It is highly efficient and eliminates the need for explicit looping and index manipulation.

For example, consider the following code:

text = "I am a very, very helpful text"

for group in chunker(text, 7):
   print(repr(group),)

# 'I am a ' 'very, v' 'ery hel' 'pful te' 'xt'

Here, the chunker function divides the text into groups of seven characters, yielding tuples of character sequences.

Similarly, you can use the chunker function to process sequences of any type, such as lists of animals:

animals = ['cat', 'dog', 'rabbit', 'duck', 'bird', 'cow', 'gnu', 'fish']

for group in chunker(animals, 3):
    print(group)

# ['cat', 'dog', 'rabbit']
# ['duck', 'bird', 'cow']
# ['gnu', 'fish']

The above is the detailed content of How Can I Efficiently Iterate Over a List in Chunks Using Python?. For more information, please follow other related articles on the PHP Chinese website!