Python Tutorials

Overview

An array is a special variable, which can hold more than one value at a time. Python does not support actual arrays, but lists can be used as arrays.

Note

Though Python does not have built-in support for arrays, Python lists can be used as pseudo “arrays”. Therefore, all Python list methods will work with these pseudo “arrays”.

Creating an Array (List)

cars = ["Ferrari", "Maserati", "Alfa Romeo"]
print(cars)

Output:

['Ferrari', 'Maserati', 'Alfa Romeo']

Accessing Items in an Array

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

x = cars[2]
print(x)

Output:

Alfa Romeo

Note

Arrays count starting from zero NOT one. So item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on.

Modifying Items in an Array

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

cars[0] = "Lamborghini"
print(cars)

Output:

['Lamborghini', 'Maserati', 'Alfa Romeo']

Get the Number of Items in an Array

The len() method is used to return the length of an array (the number of elements in an array).

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

x = len(cars)
print(x)

Output:

3

Looping Through the Items in an Array

The for in loop is used to loop through all the elements of an array.

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

for x in cars:
    print(x)

Output:

Ferrari
Maserati
Alfa Romeo

Adding Items to an Array

The append() method is used to add an element to an array.

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

cars.append("Porsche")
print(cars)

Output:

['Ferrari', 'Maserati', 'Alfa Romeo', 'Porsche']

Removing Items From an Array

The pop() method is used to remove an element from an array.

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

cars.pop(1)
print(cars)

Output:

['Ferrari', 'Alfa Romeo']

The remove() method can also be used to remove an element from an array.

cars = ["Ferrari", "Maserati", "Alfa Romeo"]

cars.remove("Maserati")
print(cars)

Output:

['Ferrari', 'Alfa Romeo']

Python Notes:

  • The most recent major version of Python is Python 3; however, Python 2 is still in use and quite popular, although not being updated with anything other than security updates
  • Python uses new lines to complete a command, as opposed to other programming languages which often use semicolons or parentheses
  • Python relies on indentation, using whitespace to define scope, such as the scope of loops, functions, and classes; other programming languages often use curly-brackets for this purpose
  • Python string methods return new values, and DO NOT change the original string
  • Python tuples are unchangeable after created (their items CANNOT be changed or re-ordered at a later point)
  • Python sets are unordered (may appear in random orders when called), unchangeable (the value of individual items cannot be changed after creation), unindexed (items cannot be referred to by index or key), and duplicates are NOT ALLOWED
  • As of v3.7, Python dictionaries are ordered and duplicates ARE ALLOWED; in v3.6 and earlier, dictionaries were unordered (did not have a defined order and could not be referred to using an index)
  • Python does not have built-in support for arrays, but Python lists can be used as pseudo “arrays”; therefore, all Python list methods will work with these pseudo “arrays”

We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.