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}