This article will cover how Python Hashmaps work and when they might be helpful and provide examples of their usage in Python code.
Table of Contents
Hashmap Python: How it works?
Hashmaps are data structures that store data in the form of a key-value pair.
The Python hashmap is an unordered collection of key-value pairs stored in a hash table where keys are unique, and the hash function maps hashable objects to hash indexes. Hash functions give more speed than binary search because hash functions reduce the number of comparisons used for searching while binary search uses comparisons to find items in sorted lists.
Python hashmaps can be defined as follows:
Hashmaps are implemented using dictionary class, i.e., dict. It works precisely like a dictionary, but it’s faster than a dictionary because all element insertion happens via hashing, so there’s no need to check existence.
Hashmap Python: How to implement Hashmap?
To learn the implementation of Hashmap in Python let’s take an example of roll numbers of a class as we cannot remember them in real life.
Example Code#01
RollNumbers={
'Harry':526272,
'Joe':648404,
'Karol':374757,
'Paul':285848,
'Rachel':171819,
'Simon':607080,
'Tom':987868,
'Jack':675747,
'Amelia':503892,
'Evelyn':213141
}
print(RollNumbers) Output
Example Code#02: Return Specific Values
So we can get the roll numbers for the specified names.
RollNumbers={
'Harry':526272,
'Joe':648404,
'Karol':374757,
'Paul':285848,
'Rachel':171819,
'Simon':607080,
'Tom':987868,
'Jack':675747,
'Amelia':503892,
'Evelyn':213141
}
print(RollNumbers.get('Simon'))
print(RollNumbers.get('Karol')) Output
Example Code#03: Add New Values
We can add new entries in the Python Hashmap.
RollNumbers={
'Harry':526272,
'Joe':648404,
'Karol':374757,
'Paul':285848,
'Rachel':171819,
'Simon':607080,
'Tom':987868,
'Jack':675747,
'Amelia':503892,
'Evelyn':213141
}
RollNumbers['Oliver']=463789
print(RollNumbers) Output:
Example Code#04: Update Existing Values
We can update the Roll Numbers of existing entries with the help of the following two ways.
RollNumbers['Paul']=999777
print(RollNumbers)
RollNumbers.update({'Tom':222333})
print(RollNumbers) Output
Example Code#05: Delete Exsiting Values
We can remove any entry from the Python hashmap.
RollNumbers.pop('Jack')
print(RollNumbers) Output
Conclusion
Hashmaps are often used for fast lookup, insertion, deletion, and storage efficiency on large datasets with a high number of items or records per item. I hope the concept of Hashmap Python is easily understandable in this article.
