Python Basics with Numpy (optional assignment)

Welcome to your first assignment. This exercise gives you a brief introduction to Python. Even if you've used Python before, this will help familiarize you with functions we'll need.

Instructions:

• You will be using Python 3.
• Avoid using for-loops and while-loops, unless you are explicitly told to do so.
• Do not modify the (# GRADED FUNCTION [function name]) comment in some cells. Your work would not be graded if you change this. Each cell containing that comment should only contain one function.
• After coding your function, run the cell right below it to check if your result is correct.

After this assignment you will:

• Be able to use iPython Notebooks
• Be able to use numpy functions and numpy matrix/vector operations
• Understand the concept of "broadcasting"
• Be able to vectorize code

Let's get started!

Updates to Assignment

This is version 3a of the notebook.

If you were working on a previous version

• If you were already working on version "3", you'll find your original work in the file directory.
• To reach the file directory, click on the "Coursera" icon in the top left of this notebook.
• Please still use the most recent notebook to submit your assignment.

List of Updates

• softmax section has a comment to clarify the use of "m" later in the course
• softmax function specifies (m,n) matrix dimensions to match the notation in the preceding diagram (instead of n,m)

About iPython Notebooks

iPython Notebooks are interactive coding environments embedded in a webpage. You will be using iPython notebooks in this class. You only need to write code between the ### START CODE HERE ### and ### END CODE HERE ### comments. After writing your code, you can run the cell by either pressing "SHIFT"+"ENTER" or by clicking on "Run Cell" (denoted by a play symbol) in the upper bar of the notebook.

We will often specify "(≈ X lines of code)" in the comments to tell you about how much code you need to write. It is just a rough estimate, so don't feel bad if your code is longer or shorter.

Exercise: Set test to "Hello World" in the cell below to print "Hello World" and run the two cells below.