dict_samples.py

#creating a new dictionary with 3 keys : name, age and balance
d = { "name": "John Doe", "age": 44, "balance": 235.5 }

#printing out the values of the dictionary using the kyes
print(d["name"])    # will display "John Doe"
print(d["age"])     # will display 44
print(d["balance"]) # will display 235.5

#using dict to create dictionaries
my_dict_1 = dict(name="John Doe", age=44, balance=235.5)
my_dict_2 = dict({ "name": "John Doe", "age": 44, "balance": 235.5 })
my_dict_3 = dict(zip(["name", "age", "balance"], ["John Doe", 44, 235.5]))
print(my_dict_1) # will print {'age': 44, 'name': 'John Doe', 'balance': 235.5}
print(my_dict_2) # will print {'age': 44, 'name': 'John Doe', 'balance': 235.5}
print(my_dict_3) # will print {'age': 44, 'name': 'John Doe', 'balance': 235.5}

# comparing the three dictionaries shows 
# these have the same keys and values
print(my_dict_3 == my_dict_2 == my_dict_1) # will print true

#using a for loop to print out values
for key, val in enumerate(d):
  print("{} = {}".format(key,val))

#the dictionary has a method called items() 
#which does basically the same
for key, val in d.items():
  print("{} = {}".format(key,val))


#index, get and update methods
my_dict_1 = dict(name="John Doe", age=44, balance=235.5)
print(my_dict_1["name"])     # will print "John Doe"
print(my_dict_1.get("name")) # will print "John Doe"

#specifying a value for a non-existing key will add the
#key-value pair to the dictionary
my_dict_1["website"] = "http://example.com"
print(my_dict_1)  # will print {'age': 44, 'name': 'Jane Doe', 'website':'http://example.com', 'balance': 235.5}

#using the update method with one named parameter
my_dict_1.update(name = "Jane Doe")
print(my_dict_1)  # will print {'age': 44, 'name': 'Jane Doe', 'website':'http://example.com', 'balance': 235.5}

#update can take a dictionary as parameter and will map the keys
my_dict_1.update({"name" = "Jane Doe", "balance" = 500})
print(my_dict_1)  # will print {'age': 44, 'name': 'Jane Doe', 'website':'http://example.com', 'balance': 500}