This Python Arrays lesson is for a beginner. Read the short notes, run each example, then change one name or number and run it again.
Most Python code uses a list where other languages say array. The array module holds only one numeric type and is less common in tutorials.
A list can mix types. An array from the array module cannot.
Example 1: Start here
Reach for a list first. Use array or NumPy only when you need their extra rules.
marks = [71, 82, 90] # a list; the values stay in this order
print(sum(marks) / len(marks)) # len counts the items
Example 2: A list used as an array
For most beginner code, a list is the array.
scores = [70, 80, 90] # a list; the values stay in this order
print(scores[1])
Example 3: Fill with zeros
Multiplying a one-item list builds a row of starting values.
slots = [0] * 4 # a list; the values stay in this order
slots[2] = 5 # change this one field
print(slots)
Example 4: The array module
array.array stores one kind of number. The i means integers.
import array # load a tool that comes with Python
scores = array.array("i", [70, 80, 90]) # the value at this position
print(scores[0])
Reach for a list first. Use array or NumPy only when you need their extra rules.
