Introduction
Java has a built-in called HashMap. It allows you to store and very quickly retrieve key value pairs.
In Python, this is called a dictionary and appears very similar to a JSON Object for those familiar with Javascript and similar languages.
Dictionaries as HashMaps
An example of a dictionary in Python is as follows:
ages = {"Bob":25, "James":54, "Darren":44}
The same can be created using the dict keyword:
ages = dict({"Bob":25, "James":54, "Darren":44})
A third way to create and populate this:
ages = {}
ages["Bob"] = 25
ages["James"] = 54
ages["Darren"] = 44
Accessing values
As per our last creation option, accessing is much the same.
# get james' age
james = ages["James"]
# it is safer to do it this way
james = 0
if "James" in ages:
james = ages["James"]
# or simply
james = 0 if "James" not in ages else ages["James"]
Deleting a value
Deleting a value is as simple as calling the key with the del keword.
del ages["James"]
This will result in the following output:
# create our dictionary/hashmap
ages = {"Bob":25, "James":54, "Darren":44}
# delete James' entry
del ages["James"]
# let's see what the dictionary contains now
print(ages)
# {'Bob': 25, 'Darren': 44}