====== 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.

===== Variables =====

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.

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

===== Printing =====

<code python>
print(a)
print("a =", a)
print("a =", a, "b =", b)
print("a = {}".format(a))
print("a = {}, b = {}".format(a, b))
</code>

===== Loops =====

Loops can use two commands, **for** or **while**.

<code python>
# loop using command for and function range
for i in range(5, 10, 2):
    print(i)
</code>

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. 

<code python>
print(list(range(3)))
print(list(range(3, 5)))
print(list(range(3, 10, 3)))
</code>

Loops using commnad **for** can be also combined with lists.

<code python>
values = ['one', 'two', 'three']
for i in values:
    print(i)
</code>

<code python>
# loop using command while
a = 5
while a > 1:
    print(a)
    a = a - 1

# note: infinite loop, common in embedded 
# while True:
#     # command
</code>

===== Branches =====

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

<code  python>
# branches and loops can be combined
for i in range(10):
    if i % 2:
        print(i)
</code>

===== Modules =====

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

<code python>
# 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)))
</code>

<code python>
# 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)))
</code>

<code python>
# 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)))
</code>