iterables_summary.py

'''Review of Lists, Tuples, Dictionaries & Sets'''


# Compare data structures
# -----------------------------------------------------------------------------
# List: mutable, ordered, values don't need to be unique
colours_list = ['red', 'orange', 'black', 'black']

# Tuple: immutable, ordered, values don't need to be unique
colours_tuple = ('red', 'orange', 'black', 'black')

# Sets: mutable, unordered, values must be unique
colours_set = {'red', 'orange', 'black'}

# Frozensets : immutable, unordered, values must be unique
colours_fset = frozenset(('red', 'orange', 'black'))

# Dict keys: immutable, ordered (as of Python 3.6), values must be unique
# Dict values: mutable, ordered (as of Python 3.6), values don't need to be unique
colours_dict = {
    'red': 'Pantone 185C',
    'orange': 'Pantone 021C',
    'black': 'Pantone 6C'
    }

print(type(colours_list))   # <class 'list'>
print(type(colours_tuple))  # <class 'tuple'>
print(type(colours_set))    # <class 'set'>
print(type(colours_fset))   # <class 'frozenset'>
print(type(colours_dict))   # <class 'dict'>

# In each case use [] brackets to access a single element
# (except sets which don't support indexing):

print(colours_list[2])        # black
print(colours_tuple[2])       # black
print(colours_dict['black'])  # Pantone 6C

# You can combine data structures, for example, you can make:
# - a tuple of lists
# - a list of lists
# - a dictionary of lists (only the values van be lists)

colors = ['magenta', 'red', 'cyan']
moods = ['happy', 'sad', 'confused']
senses = ['smell', 'touch', 'taste']

dict_of_lists = {
    'Colors': colors,
    'Moods': moods,
    'Senses': senses
    }

# Reminder: Dictionary keys are immutable, therefor you cannot use a list
# or another dictionary as a key, but you CAN use a tuple or a frozenset
# because those are immutable too. A good example of this is with mapping –
# the GPS coordinates may be the key:

places = {
    (44, -93, 344): 'home',
    (27, -80, 200): 'work'
    }

# Note that these aren't the only iterables in Python. Other iterables include:
# - strings
# - generators
# - pandas series objects