Convert Dictionary to List of Tuples in Python

Dictionary to Tuples

Python dict objects have many useful methods for handling data. One method that is useful for accessing data and converting it to a list of tuples is the dict.items() method.

my_data = {
    "Joe": 1,
    "Jane" : 2,
    "Alice" : 3,
    "Bob" : 4
}

print(list(my_data.items()))

[('Joe', 1), ('Jane', 2), ('Alice', 3), ('Bob', 4)]

The dict.items() method returns a view object, which reflects the current state of the dictionary. Notice the difference in output between the following snippets:

my_data = {
    "Joe": 1,
    "Jane" : 2,
    "Alice" : 3,
    "Bob" : 4
}

my_tuple_view = my_data.items()
print(my_tuple_view)

my_data["Joe"] = 2
print(my_tuple_view)

dict_items([('Joe', 1), ('Jane', 2), ('Alice', 3), ('Bob', 4)])
dict_items([('Joe', 2), ('Jane', 2), ('Alice', 3), ('Bob', 4)])

Note that my_tuple_view reflects the changes in my_data. However, if we cast it as a list:

my_data = {
    "Joe": 1,
    "Jane" : 2,
    "Alice" : 3,
    "Bob" : 4
}

my_tuple_list = list(my_data.items())
print(my_tuple_list)

my_data["Joe"] = 2
print(my_tuple_list)

[('Joe', 1), ('Jane', 2), ('Alice', 3), ('Bob', 4)]
[('Joe', 1), ('Jane', 2), ('Alice', 3), ('Bob', 4)]

Now, my_tuple_list values aren't associated to my_data values anymore. Keep this in mind when using the dict.items() method.

One interesting application of the dict.items() method is applying some function to each element of the dictionary, using both the keys and values:

my_data = {
    "Joe": 1,
    "Jane" : 2,
    "Alice" : 3,
    "Bob" : 4
}

my_map = lambda tup : tup[0] + '_' + str(tup[1])
print(list(map(my_map, my_data.items())))

['Joe_1', 'Jane_2', 'Alice_3', 'Bob_4']