Basics

This page will be updated as we get a better grasp of incoming members' Python background. For Python beginners, the official Python tutorial is a very good resource to pick up the language as you work through the exercise in the following section.

Running Python code

The Python interpreter can be accessed interactively in the terminal:

$ python
Python 3.12.0 (main, Oct  2 2023, 17:01:41) [Clang 14.0.0 (clang-1400.0.29.202)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, world!")
Hello, world!
>>> 1 + 2
3
>>>

Depending on your Python installation, you may need to use python3 or py instead of the python command.

But, for larger scripts, it's better to write Python code into a file, which can be run later. For example, try creating a file called hello_world.py with the contents:

print("Hello, world!")

We can then run this file in the terminal:

$ python hello_world.py
Hello, world!

It should also possible to run the file using the "Run" button in your editor of choice.

Simple examples

Many of the following code snippets have been taken from the official Python tutorial. The purpose of this section is to give a very broad overview of what Python looks like. The hope is that you will learn the relevant parts of Python as you need them, while you work on the telemetry pipeline as part of this training. To learn the language more thoroughly, please refer to that tutorial.

Variables in Python are declared using the [name] = [value] syntax, and messages can be output to the screen using the print function:

i = 256 * 256
print("The value of i is", i) # output: The value of i is 65536

On any line, everything after a # is a comment. They do not affect to behavior of your code.

# This is a comment.
x = 1 # This is also a comment.
# x = 2
print(x) # output: 1

Python defines a set of default types available to use in your code, including integers, floating point (fractional) numbers, complex numbers, booleans (true/false), strings (text), lists, and much more.

an_integer = -10
a_float = 1.5
a_complex_number = 1 + 2j
a_boolean = True
a_string = "This is a string!"
a_list = [1, 2, 3, 4, 5]

Python programmers can use the if, elif, and else keywords to cause different behavior depending on given conditions.

x = 5
if x < 0:
    x = 0
    print('Negative changed to zero')
elif x == 0:
    print('Zero')
elif x == 1:
    print('Single')
else:
    print('More') # output: More

for and while loops can be used to repeat certain behavior. Loops are commonly used to iterate over collections, like lists. For example:

a = ['Mary', 'had', 'a', 'little', 'lamb']
for i in range(len(a)):
    print(i, a[i]) # output:
                   # 0 Mary
                   # 1 had
                   # 2 a
                   # 3 little
                   # 4 lamb

Functions are blocks of code which can defined once and called many times later. Functions are Python are defined using the def keyword:

def fib(n): # write Fibonacci series up to n
    a, b = 0, 1
    while a < n:
        print(a, end=' ')
        a, b = b, a+b
    print()

# Now call the function we just defined:
fib(100) # output: 0 1 1 2 3 5 8 13 21 34 55 89
fib(2000) # output: 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

Sometimes you'll want to use code that someone else wrote or that lives in a different file in your own project. You can do this with the import statement.

import math

print(math.sin(0.5)) # output: 0.479425538604203

Here, we imported the math module from Python's standard library to calculate the sine of 0.5. The standard library is automatically available to your Python program. Other packages must be installed before they can be used.

These examples only scratch the surface of what there is to learn about Python. Again, there are many good online resources that go into much more detail!