0) Introduction to Python

This introductory page explains how to install Python and Spyder, and provides a brief overview of Python programming. You will also have access codes to a great StudyLens app to quickly get a grasp of Python programming, especially the parts directly relevant to this course.

Installing Spyder and Anaconda

To best way to install Spyder is to do so via Anaconda, which is a free and open-source distribution of Python for scientific computing. You can download Anaconda from this page (note: use the download link on the left, and not the one called “miniconda” which does not include Spyder). After downloading, follow the installation instructions.

Once done, you now have:

  • Python
  • Spyder (our main editor)
  • Most scientific packages like numpy, matplotlib, and pandas
  • Conda and pip (for if you want to install other packages)

Launching Spyder

You can now launch Spyder via the ‘Anaconda Navigator’ application. In MacOS you find this under ‘Applications’ > ‘Anaconda-Navigator’ (it doesn’t always show up in the Spotlight search immediately). In Windows, you can search for ‘Anaconda Navigator’ in the Start Menu. Once the Anaconda Navigator is open, you can launch Spyder by clicking on the ‘Launch’ button under the Spyder icon.

Disabling inline plots

By default, Spyder shows figures inside the “Plots” pane, but in this course we typically use plots that update dynamically (animations), which don’t work well in that mode. So we need to change that.

Here’s how:

  1. Click the ‘preferences’ icon in the top panel (a wrench icon 🔧).
  2. Go to ‘IPython Console’ → Graphics → Backend
  3. Choose Qt, Qt5, or Qt61
  4. Click Apply and OK
  5. Restart Spyder may or may not be necessary depending on your operating system.

Now your plots will open in a separate window and can animate properly!

Testing your setup!

Throughout this course you will either work with scripts you have been handed out, or scripts that you can copy/paste from this website. Let’s test your Spyder setup with the following script:

import random, matplotlib.pyplot as plt

plt.ion()
fig, ax = plt.subplots()
ax.set_ylim(-2, 2)
ax.set_xlim(0, 100)
ax.set_title("Random Wiggle Test")
line, = ax.plot([], [], color='seagreen', lw=2)

y = [0]
for i in range(100):
    y.append(y[-1] + random.uniform(-0.1, 0.1))  # random wiggle
    line.set_data(range(len(y)), y)
    ax.set_xlim(0, len(y))
    plt.pause(0.03)

ax.set_title("Animation works! (you can close this window)")
plt.ioff()
plt.show()

Paste this into a new script in Spyder and hit the ‘play’ icon (or press F5). Does the animation show up in a seperate window and is it animated? Good, you’re ready to go!

Installing VS code

Instead of Spyder, you may want to use a nicer IDE. The most popular one is currently Visual Studio Code (VS Code). To install VS Code and connect it to your Anaconda3 python installation, do the following:

  1. Download and install VS code (https://code.visualstudio.com/download)
  2. Open VS code and install the Python extension (search for ‘Python’ in the extensions tab on the left, and install the one with the blue check mark)
  3. Select the python interpreter that comes with Anaconda. You can do this by pressing Ctrl+Shift+P (or Cmd+Shift+P on Mac) to open the command palette, then type Python: Select Interpreter and choose the one that points to your Anaconda installation (it should have ‘anaconda3’ in the path).

Now, you should be able to run all the code from the course via VS code as well! While Spyder is nice, it also is a little less stable than VS code, so if you run into issues, consider switching to VS code! :)

Introduction to Python Programming

This document provides a brief introduction to Python programming. It covers basic concepts such as variables, data types, control structures, functions, and libraries.

Variables and Data Types

In Python, variables are used to store data. You can create a variable by assigning a value to it using the = operator. For example:

x = 10
y = "Hello, World!"

Python has many built-in data types, including:

  • Integers (int): Whole numbers, e.g., 10, -5
  • Floating-point numbers (float): Decimal numbers, e.g., 3.14, -0.001
  • Strings (str): Text, e.g., "Hello", 'Python'
  • Booleans (bool): True or False values, e.g., True, False
  • Lists (list): Ordered collections of items, e.g., [1, 2, 3], ['a', 'b', 'c']
  • Dictionaries (dict): Key-value pairs, e.g., {'name': 'Alice', 'age': 25}
  • And many more

Control Structures

Control structures allow you to control the flow of your program. Common control structures in Python include:

  • Conditional statements (if, elif, else):
if x > 0:
    print("x is positive")
elif x == 0:
    print("x is zero")
else:
    print("x is negative")
  • Loops (for, while):
for i in range(5):
    print(i)
count = 0
while count < 5:
    print(count)
    count += 1

Functions

Functions are reusable blocks of code that perform a specific task. You can define a function using the def keyword:

def greet(name):
    return f"Hello, {name}!"
    
print(greet("Alice"))

Libraries

Python has a rich ecosystem of libraries that extend its functionality. Most scientific packages are shipped with Anaconda, so you don’t need to worry about these. These include:

  • NumPy: For numerical computing
  • Pandas: For data manipulation and analysis
  • Matplotlib: For data visualization
  • SciPy: For scientific computing

But if you still wish to install other packages, you can use pip or conda in the terminal. For example, to install the html5 library using pip, you would run:

pip install html5lib

From the command line. You can also run this bit of code within the Spyder console by adding an ! in front of the command, which tells the console to run it as a shell command:

!pip install html5lib

But you probably won’t have to install a lot of packages during this course. (nearly) All scripts we use only rely on the base packages.

StudyLens practice

If you’ve installed Python and read through the basics of Python above, it’s time to dive into the StudyLens exercises. For this, login to StudyLens and use the username and password that was shared with you on Brightspace.

  1. on some laptops, Tk may be faster, but DON’T use ‘inline’↩︎