Dictionary Methods¶

Date published: 2018-03-26

Category: Python

Subcategory: Beginner Concepts

Tags: dictionaries

Dictionaries have methods that allow for modification of dictionary structures. I'll cover a few important ones in this tutorial.

Access dictionary keys¶

The keys() method outputs a dict_keys object that presents a list of a dictionary's keys.

In [2]:

dan = {'name': 'Dan Friedman', 'location': 'San Francisco', 'profession': 'Data Scientist'}

dan = {'name': 'Dan Friedman', 'location': 'San Francisco', 'profession': 'Data Scientist'}

In [6]:

dan.keys()

dan.keys()

Out[6]:

dict_keys(['name', 'location', 'profession'])

Access dictionary values¶

The values() method outputs a dict_values object that presents a list of a dictionary's values.

In [7]:

dan.values()

dan.values()

Out[7]:

dict_values(['Dan Friedman', 'San Francisco', 'Data Scientist'])

Loop over key-value pairs¶

The items() method outputs a dict_items object that's a sequence of tuples in which each tuple is a key-value pair.

In [8]:

dan.items()

dan.items()

Out[8]:

dict_items([('name', 'Dan Friedman'), ('location', 'San Francisco'), ('profession', 'Data Scientist')])

We can iterate over this dict_items object in a for loop.

In [10]:

for key, value in dan.items():
    print("A key of {0} corresponds to a value of {1}".format(key, value))

for key, value in dan.items(): print("A key of {0} corresponds to a value of {1}".format(key, value))

A key of name corresponds to a value of Dan Friedman
A key of location corresponds to a value of San Francisco
A key of profession corresponds to a value of Data Scientist