dictionaries

various independent examples of creating and calling dictionaries

basic dictionary functions

sample_dict = {'weather': 'beautiful', 'tea': 'iced', 'age': 29} print(sample_dict['weather'])

updating dictionary values, printing individual values, deleting an item(key and value)

stock = {'oranges': 10, 'apples': 5, 'pears': 10} print(stock) stock['oranges'] = 13 stock['apples'] = 9 stock['pears'] = 14 print(stock) stock['pears'] += 1 print(stock) print(stock['pears']) print(stock['apples']) del stock['oranges'] print(stock) stock['cherries'] = 4 print(stock)

when printed:

beautiful {'oranges': 10, 'apples': 5, 'pears': 10} {'oranges': 13, 'apples': 9, 'pears': 14} {'oranges': 13, 'apples': 9, 'pears': 15} 15 9 {'apples': 9, 'pears': 15} {'apples': 9, 'pears': 15, 'cherries': 4}

checking for membership inside a dictionary

stock = {'oranges': 10, 'apples': 5, 'pears': 10} print('apples' in stock) print('grapes' in stock) print('lollipop' not in stock)

sell some oranges

stock['oranges'] -= 2 print(stock)

add 3 apples to the stock

stock['apples'] += 3 print(stock)

we are out of pears

del stock['pears'] print(stock)

is there pizza in stock ?

print('pizza' in stock)

when printed:

True False True {'oranges': 8, 'apples': 5, 'pears': 10} {'oranges': 8, 'apples': 8, 'pears': 10} {'oranges': 8, 'apples': 8} False

let's create a list of all the keys and values and pairs as well from the dictionary

stock = {'oranges': 10, 'apples': 5, 'pears': 10} fruits = stock.keys() print(fruits) number_available = stock.values() print(number_available) together = stock.items() print(together)

when printed:

dict_keys(['oranges', 'apples', 'pears']) dict_values([10, 5, 10]) dict_items([('oranges', 10), ('apples', 5), ('pears', 10)])

converting a dictionary into a list and a list into a dictionary

stock = {'oranges': 10, 'apples': 5, 'pears': 10} print(list(sorted(stock.keys())))

when printed:

['apples', 'oranges', 'pears']

more ditionary functions:

def fillable(stock, merch, n): if n <= stock[merch]: return True if n >= stock[merch]: return False stock = {'apples': 12, 'bananas': 14, 'oranges': 6} print(fillable(stock, 'apples', 14)) print(fillable(stock, 'bananas', 12)) fillable(stock, 'oranges', 12)

when called:

False True False

turning a list into a dictinoary

def user_contacts(lst): dictionary = {} for person in lst: name = person[0] if len(person) > 1: code = person[1] else: zip_code = None dictionary[name] = code return dictionary

lst = [["Grae Drake", 98110], ["Bethany Kok"], ["Alex Nussbacher", 94101], ["Darrell Silver", 11201]] user_contacts(lst)

when called:

{'Alex Nussbacher': 94101, 'Bethany Kok': 98110, 'Darrell Silver': 11201, 'Grae Drake': 98110}