How Does Python's Zip Function Actually Work with Multiple Lists?

Understanding Python's Zip Function: Unzipping the Mystery

When working with multiple lists of equal length, one often seeks to combine them into a single dataset. This is where Python's zip function shines. However, a common pitfall arises when misunderstandings surround the expected outcome.

To illustrate this, consider a scenario where three lists, x1, x2, and x3, each containing 20 elements, are created. Upon calling zip(x1, x2, x3), one might anticipate a list of three elements. However, what you actually get is a list of 20 three-tuples.

Confused? Don't worry, the underlying reason is simple. zip operates by combining elements from corresponding indices in the input lists. In this case, it creates 20 tuples, each consisting of one element from x1, one from x2, and one from x3. The misconception stems from the assumption that zip produces a list of lists instead of a list of tuples.

To demonstrate this:

a = b = c = range(20)
result = zip(a, b, c)

print(result)
# Output: [(0, 0, 0), (1, 1, 1), ... (19, 19, 19)]

print(len(result))
# Output: 20

print(len(result[0]))
# Output: 3

As seen above, result contains 20 three-tuples, each of which holds three elements. To determine the number of elements in each tuple, examine the length of the first tuple.

The above is the detailed content of How Does Python's Zip Function Actually Work with Multiple Lists?. For more information, please follow other related articles on the PHP Chinese website!