Lesson 05-02: Looping over Lists

Learning Target: I can use a for loop to iterate over every element in a list.
Learning Target: I can use a for-each loop to iterate over every element in a list.

Looping by Referencing Index

We know that we can use a for loop to iterate through a list of numbers. This lets us iterate through every position in a list:

However, in python, there’s a much easier way!

Using a for-each loop

We can use a for each loop to do the same thing as above:

In our first example with i, i represented the index of each element of a. However, in this example, item represents the element itself! This is called a for-each loop because it runs a loop for each element in a list.

In case you’re wondering why this is, recall that range() is a function that generates a LIST of numbers! All you’re doing is iterating through that list! So really, every for loop in python is a for-each loop!

Checks for Understanding

Q#1

INSTRUCTIONS: Write a for loop below so it will print out every element in the list names.

Q#2

INSTRUCTIONS: Given a list of integers numbers, return the sum of the elements in numbers.

Q#3

INSTRUCTIONS: Given a list of letters letters, return the count of vowels in the list.

Next Section - Lesson 05-03: Basic List Functions