In this lab, we introduced several major important topics in Python. Let’s quickly review them.
Lists in Python allow us to store multiple elements in a single variable, with each element identified by a unique index within the list.
Lists can be created using square brackets
list_a =  list_b = [5, 3, 7]
Adding and Accessing List Items
New elements can be added to a list using the
list_a =  list_a.append(4)
Items in a list can be accessed and updated using square brackets:
list_b = [5, 3, 7] list_b = list_b + list_b
Loops with Lists
Lists can be iterated using both for loops and while loops:
list_b = [5, 3, 7] for i in list_b: print(i) j = 0 while j < len(list_b) print(list_b[j]) j = j + 1
Lists should not be changed while iterating using a for loop.
Functions with Lists
When calling a function that accepts a list as a parameter, the argument is passed using call by reference instead of call by value. The original list can be modified by the function, but it cannot be replaced with a new list unless the reference to that new list is returned from the function.
Strings as Lists
Strings can be iterated just like a list, and we can use square brackets to access individual characters in a string. However, strings (unlike lists) are still passed as call by value when provided as an argument to a function.
We can create a slice of a list by specifying a
step value separated by colons. The values may be omitted, and may also be negative.
list_b = [5, 3, 7] print(list_b[-1]) print(list_b[0:1]) print(list_b[0:2:2]) print(list_b[::-1])