Some brief unorganized notes on things I covered today:

Control flow and iterables.

enumerate(iterable) - yields pairs containing index and the value at index from iterables e.g. (0, seq[0]), ...). Neater way of iterating through collections like lists.

Functions

*args and **kwargs finally clicked while working through some trivially simple examples.

fn(*args) - can take any number of positional arguments, returns a tuple.

def varargs(*args):
    return(args)

varargs('one', (3,), [4,5,6,7], 8732.32)

# returns
('one', (3,), [4, 5, 6, 7], 8732.32)

fn(**kwargs) - takes any number of keyword arguments, returns dictionary.

def kwargs(**kwargs):
    return(kwargs)

kwargs(first="Liverpool", second="Nottingham Forest", third="Arsenal")

# returns
{'first': 'Liverpool', 'second': 'Nottingham Forest', 'third': 'Arsenal'}

within a function, global x invokes a variable x that’s in the global scope. while in an inner loop nonlocal x, y accesses those variables outside its local scope.

also new to me, the idea of functions that return a function. Can’t picture use cases at the moment.

def create_avg():
	total = 0
	count = 0
	def avg(n):
		nonlocal total, count
		total += n
		count += 1
		return total/count
	return avg

avg = create_avg()

avg(3) # => 3.0
avg(5) # (3+5)/2 => 4.0
avg(7) # (8+7)/3 => 5.0

other things covered today: lambda functions, comprehensions (list, set, dict), and modules. tip: dir(math) shows functions and attributes in a module.

Touched a bit on Classes. Corey Schafer’s, Python OOP Tutorials - Working with Classes, was helpful in building the intuition. Saved for future reference.

Tomorrow: Work through chapter 1 of Practical Python Programming.