Python basics

Since in the course, we will be trying to program the Raspberry Pi Pico in MicroPython, it is necessary to familiarize ourselves with at least the basics of the Python programming language.

A variable is a fundamental element of programming abstraction that provides a symbolic name for a location in memory occupied by binary data. The meaning of binary data is then represented in the program through a data type. Data type can describe binary data as mode complex entities, like integer of float numbers, strings, arrays, dictionaries, etc.

a = 10          # integer
b = 3.14        # float
c = "hello"     # string
d = [1, 2, 3]   # list
e = {"id": 10}  # dictionary

print(a)
print("a =", a)
print("a =", a, "b =", b)
print("a = {}".format(a))
print("a = {}, b = {}".format(a, b))

Loops can use two commands, for or while.

# loop using command for and function range
for i in range(5, 10, 2):
    print(i)

Function range(begin, end, step) generally returns sequence of numbers from begin to end-1 with step. If begin is not given, then its value is 0, default step is 1. In following example are ranges recasted to lists.

print(list(range(3)))
print(list(range(3, 5)))
print(list(range(3, 10, 3)))

Loops using commnad for can be also combined with lists.

values = ['one', 'two', 'three']
for i in values:
    print(i)

# loop using command while
a = 5
while a > 1:
    print(a)
    a = a - 1
 
# note: infinite loop, common in embedded 
# while True:
#     # command

# branch
a = 10
if a > 5:
    print("a is bigger than 5")
else:
    print("it is not bigger")

# branches and loops can be combined
for i in range(10):
    if i % 2:
        print(i)

Some functionalities can be distributed to modules. For example module math contains math functions.

# import of whole library
import math
print("sin(0.22) = {:.4f}, and cos(0.22) = {:.4f}".format(math.sin(0.22), math.cos(0.22)))

# import library with acronyme
import math as m
print("sin(0.22) = {:.4f}, and cos(0.22) = {:.4f}".format(m.sin(0.22), m.cos(0.22)))

# import just necessary functions
from math import sin, cos
print("sin(0.22) = {:.4f}, and cos(0.22) = {:.4f}".format(sin(0.22), cos(0.22)))