What is the difference between arrays and lists?

Arrays (from the array module) and lists (list) in Python are used to store collections of elements, but they have key differences:

• Data type:

  • Lists can store elements of different data types.
  • Arrays can only store elements of one data type.

• Size:

  • List size is dynamic (it changes).
  • Array size is fixed upon creation (although some operations can create a new array).

• Performance:

  • Arrays are generally more memory-efficient and faster for numerical operations due to homogeneous data type and dense packing.
  • Lists are more flexible but may be less memory-efficient for homogeneous numerical data because they store object references.

• Operation support:

  • Lists have a wider range of methods for working with elements (adding, removing, inserting, etc.).
  • Arrays have a more limited set of methods but support some operations specific to homogeneous data (e.g., conversion to bytes).

Example usage:

# List example
my_list = [1, "hello", 3.14, True]

# Array example (data type 'i' - signed integer)
import array
my_array = array.array('i', [1, 2, 3, 4, 5])