In order to access the dictionary's values you will need the key. Consider a dictionary of networking ports: In order to access the dictionary's values you will need the key. Consider a dictionary of networking ports:

Port = {80: “HTTP”, 23 : “Telnet”, 443 : “HTTPS”}

Let's learn by example:

>>> port = {80: "HTTP", 23 : "Telnet", 443 : "HTTPS"}
>>> port[80]
'HTTP'
>>> port[443]
'HTTPS'

In order to access the dictionary's value, use the square brackets along with the key. What happens if the key is not in the dictionary?

>>> port[21]

Traceback (most recent call last):
 File "<pyshell#4>", line 1, in <module>
 port[21]
KeyError: 21
>>>

If the key is not found, then the interpreter shows the preceding error.