====== Bra moduler ======


  * pyserial -- Comport
  * matplotlib -- Matlabliknande plotverktyg
  * [[python:numpy]] -- Matlabliknande matte
  * pandas -- Importera och exportera till olika filformat, ex CSV, tydligen också för att behandla data


[[https://docs.python.org/3/reference/|Official reference]]

====== Saker jag vill ha svar på ======

  * Grundläggande datastrukturer i Python
  * Grundläggande datastrukturer i NumPy
  * Grundläggande datastrukturer i Pandas
  * Grundläggande datastrukturer i Matplotlib
  * Hur man läser syntaxguide i pythons dokumentation
  * Hur man använder context managers
  * Vad är generators, hur fungerar yield
  * Vem fan kom på syntaxen ''mylist = [x*x for x in range(3)]'' och när kan den användas?
  * ^ Verkar vara [[https://www.w3schools.com/python/python_lists_comprehension.asp|List comprehensions]]
====== Cheat sheet ======

<code python>
empty_list = []

# Tuples are immutable, can contain different datatypes
empty_tuple = ()
populated_tuple = (1, 2, "Kalle", 4.32)
singleton_tuple = (3,)
print(populated_tuple[2]) # Prints Kalle

# Ranges are also immutable
r1 = range(0,20,2) # Start stop step

# Strings
single_str = 'Single quotes allows "double quotes" to be embedded'
double_str = "Single quotes allows 'single quotes' to be embedded"
triple_str = '''Can be initiated with either single or double quotes
                and can span multiple lines, including all whitespaces.'''
no_escape = r"This string doesn't escape where the \backslash character is encountered"
concatenation = 'Literals' " can be concatenated" ''' in this
way actually'''


# Dictionaries, keys must be hashable
>>> a = dict(one=1, two=2, three=3)
>>> b = {'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({'three': 3, 'one': 1, 'two': 2})
>>> a == b == c == d == e
True
>>> empty_dict = {}

my_dict = {'shit': 1337, 'man': 2021, 'dude':1991}
all_keys = list(my_dict)
leet = my_dict['shit']

# Dictionaries can be unpacked and used as arguments to a function
dude = {a: 4, b: 5}
function_that_takes_a_and_b(**dude)

# Set types must contain hashable objects. They are not ordered and cannot be indexed
>>> my_pants = {1, 2, 'shit', 'dude'}
>>> 'shit' in my_pants
True

# Byte objects are very similar to strings, but each character has a value 0-255
# They are created in the same way, but with the prefix 'b'
my_bytes = b'Yoman!'
ten_zero_bytes = bytes(10)
int_to_bytes = bytes([10])
int_to_bytes_again = bytes([10, 4, 21, 0, 255])
my_bytes = 'This is a string'.encode()
my_str = my_bytes.decode()


# Print formatted outputs
print("Id: {0}, value: {1:02X}\n".format(my_id, my_hex_value))

# Print without newline
print("No newline after this!", end='')

</code>

====== Classes and objects ======

<code python>

# Name mangling for double underscore and less than one trailing underscores
class Foo(object):
    yo = None     # => foo_object.yo
    _yo = None    # => foo_object._yo
    __yo = None   # => foo_object._Foo__yo
    __yo__ = None # => foo_object.__yo__


# To copy an object
import copy
inst2 = copy.copy(inst1)
</code>


====== Argument parser ======

<code python>
import argparse

def parse_arguments():
    parser = argparse.ArgumentParser(description="Some description",epilog="Huh?")

    parser.add_argument('integers', metavar='N', type=int, nargs='+', 
                         help='an integer for the accumulator')

    parser.add_argument('--sum', dest='accumulate', action='store_const',
                         const=sum, default=max, help='sum the integers (default: find the max)')

    parser.add_argument('-v', '--verbose', action='store_true', help='Verbose mode')

    args = parser.parse_args()
    return args
    

def main():
    args = parse_arguments()
    if args.verbose:
        print(dir(args))

if __name__ == '__main__':
    main()
</code>

====== Signals ======
[[https://docs.python.org/3/library/signal.html|Signals python documentation]]
<code python>
import signal

def signal_handler_C_c(sig, frame):
    print('C-c detected, exiting..')
    
def main():
    signal.signal(signal.SIGINT, signal_handler_C_c)
    
</code>


====== Exceptions ======
[[https://docs.python.org/3/tutorial/errors.html]]

[[https://docs.python.org/3/library/exceptions.html|Predefined exceptions]]

<code python>
# Catch exceptions
a_list = ['yo', 'man']
try:
  print(a_list[3])
except IndexError:
  print("Index out of range! :(")


a_list = ['yo', 'man']
try:
  print(a_list[3])
except Exception as e:
  print("Ett fel har uppstått...")
  print(e)
  print(type(e))
</code>

<code python>
# Raise exceptions:
raise ValueError("Passed array is not of the right shape")
</code>

====== Decorators ======
Syntactic sugar based on functions that return function objects.

[[https://www.programiz.com/python-programming/decorator|Good guide]], much of the info here is stolen from this site.

===== Basics =====

<code python>
# Given this function, which is called a decorator function
def my_decorator(func):
    def wrapper():
        print("I got decorated!")
        func()
    return wrapper

# Then one could write something like this
def boring():
    print("Normal function")
    
pimped_boring = my_decorator(boring)
pimped_boring()

# Or one could overwrite the boring function name
def boring():
    print("Normal function")
boring = my_decorator(boring)

# which is equivalent to write this short-cut syntax
@my_decorator
def boring():
    print("Normal function")
</code>

===== Chaining =====

<code python>
# Given the two decorators
def star(func):
    def inner(*args, **kwargs):
        print("*" * 30)
        func(*args, **kwargs)
        print("*" * 30)
    return inner


def percent(func):
    def inner(*args, **kwargs):
        print("%" * 30)
        func(*args, **kwargs)
        print("%" * 30)
    return inner
    
# Then 
@star
@percent
def printer(msg):
    print(msg)
    
# is equivalent to
def printer(msg):
    print(msg)
printer = star(percent(printer))
</code>
===== Property decorator and setter decorators =====
[[https://stackoverflow.com/questions/17330160/how-does-the-property-decorator-work-in-python|Explained at stackoverflow]]

<code python>
class MyClass(object):
    def __init__(self):
        self._my_property_value = None # Placeholder variable, so getter function works
        self.my_property = 123 # Will call the proper setter function
        
    @property
    def my_property(self):
        return self._my_property_value
        
    @my_property.setter
    def my_property(self, value):
        if value < 0:
            self._my_property_value = -value * 10
        else:
            self._my_property_value = value/10
            
my_instance = MyClass()
my_instance.my_property = -30
print(my_instance.my_property) # Prints 300
</code>


====== tkinter ======
[[https://tkdocs.com/tutorial/menus.html|Good site]]

[[https://tcl.tk/man/tcl8.6/TkCmd/contents.htm|tk reference]]

[[https://web.archive.org/web/20200201190621/http://effbot.org/tkinterbook/text.htm|Archived tutorial from effbot.org]]