Dictionaries

phonebook = {}
phonebook["John"] = 938477566
phonebook["Jack"] = 938377264
phonebook["Jill"] = 947662781
print(phonebook)

# {'John': 938477566, 'Jill': 947662781, 'Jack': 938377264}

phonebook = {
    "John" : 938477566,
    "Jack" : 938377264,
    "Jill" : 947662781
}
print(phonebook)

# {'John': 938477566, 'Jill': 947662781, 'Jack': 938377264}

Iterating over dictionaries

Dictionaries can be iterated over, just like a list. However, a dictionary, unlike a list, does not keep the order of the values stored in it. To iterate over key value pairs, use the following syntax:

phonebook = {"John" : 938477566,"Jack" : 938377264,"Jill" : 947662781}
for name, number in phonebook.items():
    print("Phone number of %s is %d" % (name, number))

# Phone number of John is 938477566
# Phone number of Jill is 947662781
# Phone number of Jack is 938377264

Removing a value

phonebook = {
   "John" : 938477566,
   "Jack" : 938377264,
   "Jill" : 947662781
}
del phonebook["John"]
print(phonebook)

# {'Jill': 947662781, 'Jack': 938377264}

phonebook = {
   "John" : 938477566,
   "Jack" : 938377264,
   "Jill" : 947662781
}
phonebook.pop("John")
print(phonebook)

# {'Jill': 947662781, 'Jack': 938377264}

iter()

>>> m = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
...      'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
>>> for key in m:
...     print(key, m[key])

#[Output]
Jan 1
Feb 2
Mar 3
Apr 4
May 5
Jun 6
Jul 7
Aug 8
Sep 9
Oct 10
Nov 11
Dec 12

L = [('Italy', 'Rome'), ('France', 'Paris'), ('US', 'Washington DC')]
dict(iter(L))

# {'Italy': 'Rome', 'France': 'Paris', 'US': 'Washington DC'}