python-t.txt

Charles Truscott Watters, MIT Python

declarative vs. imperative knowledge

int, float, string, set, tuple, list, dictionary, class, object, function, function invocation, function return
combined type, expression, operator, operand

+ - * / // % ** ( ) != == and, or, not += -= *= /= //= %= **= 
& | ^ ~ << >> &= |= ^= ~= <<= >>= . * ** [ ] [i:j] [i:j:k] [i][j] [i][j][k]
: ; __ , = @

True, False, lambda x: x ** 2, lambda x, y: x ** y, yield, from x import y as z

break, continue, is, is not, in, is in

assert, global, nonlocal, pass, del

try:
	body
except ValueError:
	body
except IOError:
	body
finally:
	body
else:
	body

if filename.endswith(".txt") == False: raise ValueError("Must end with .txt, other data formats not supported")

Exception Handling, Exception Handling Classes

for x in range(start, stop - 1, step):

for x in a:
	for y in x:

for x in a:
	for y in b:

while(True):
	body
while(bool):
	while(bool):
		body

def recurse(a, b):
	base case x:
	base case y:
	base case z:
	body:
	recurse(a - 1, b - 1)
	return

recursion, iteration

if (bool):
	if (bool):
		if (bool):

		elif (bool):
		elif (bool):
		else:
	elif (bool):
	elif (bool):
	else:

elif (bool):
elif (bool):
else:

match(case / object):
	case x:
		body
	case y:
		body
	case z:
		body

branching, control flow, conditionals

def function(args):
	body
	return

def main():
	body

if __name__ == "__main__": main()

abstraction, decomposition, function-oriented programming

class Person(object):
	def __init__(self, name, age, dob):
		self.name = name
		self.age = age
		self.dob = dob
	def __repr__(self):
		pass
	def __iter__(self):
		pass
	def __str__(self):
		pass

encapsulation, inheritance, polymorphism, data and method attributes, generators, decorators

Python Standard Library, Algorithmic Complexity, Algorithms and Data Structures, Sorting and Searching, Requirements Analysis and Software Prototyping


Algorithmic Complexity

	- step

	- random access machine

	- time constraint

	- best case, worst case, average case
		- lower, upper bound

	- O(n), asymptotic notation, upper bound

	- ϴ(n), theta notation, lower bound

	- counting steps, branches, operators, operations, iteration, recursion, variables

	- order of growth in respect of some variable `n`

	constant, linear, logarithmic, log-linear, polynomial (e.g. binomial trinomial quadratic), exponential time

	- additive and multiplicative constants

e.g. prime number discovery algorithm is 5n + n / 2 for ϴ(n) but e^(5n + n / 2) for large n such as O(n)

Thursday 5 January 2023

Charles Truscott