- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Found 35163 Articles for Programming
148 Views
dicts in python are heavily optimized. Creating a dict from N keys or key/value pairs is O(N), fetching is O(1), putting is amortized O(1), and so forth. You dont need to optimize them explicitly. You can be sure of this as python under the hood implements its own classes using dicts.Don't compare lists/tuples to dicts/sets though as they solve different problems.
163 Views
Yes, Python Dictionary is mutable. Changing references to keys doesn't lead to the creation of new dictionaries. Rather it updates the current dictionary in place. examplea = {'foo': 1, 'bar': 12} b = a b['foo'] = 20 print(a) print(b)OutputThis will give the output −{'foo': 20, 'bar': 12} {'foo': 20, 'bar': 12}
941 Views
Python and javascript both have different representations for a dictionary. So you need an intermediate representation in order to pass data between them. The most commonly used intermediate representation is JSON, which is a simple lightweight data-interchange format.The dumps function converts the dict to a string. exampleimport json my_dict = { 'foo': 42, 'bar': { 'baz': "Hello", 'poo': 124.2 } } my_json = json.dumps(my_dict) print(my_json)OutputThis will give the output −'{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}'exampleThe load's function converts the string back to a dict. import json my_str = '{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}' my_dict ... Read More
582 Views
The dictionary consists of a number of buckets. Each of these buckets containsthe hash code of the object currently stored (that is not predictable from the position of the bucket due to the collision resolution strategy used)a pointer to the key objecta pointer to the value objectThis sums up to at least 12 bytes on a 32bit machine and 24 bytes on a 64bit machine. The dictionary starts with 8 empty buckets. This is then resized by doubling the number of entries whenever its capacity is reached.
501 Views
There are some cases where you can simply avoid using dictionaries in python. For example, if you're creating a dict of continuous integers to some values, consider using a list instead.If you're creating string-based keys, you might be better off using a Trie data structure(http://en.m.wikipedia.org/wiki/Trie).There are other cases where you can replace the use of dicts by some other less memory intensive data structure.But you need to understand that at some places, you have to use a dict as it helps in optimization. The python dict is a relatively straightforward implementation of a hash table. This is how hash tables ... Read More
86 Views
There will never be redundant combinations in a Python dictionary because it is a hashmap. This means that each key will have exactly one associated value with it. This value can be a list or another dict though. So if you try to add a duplicate key likeExamplea = {'foo': 42, 'bar': 55} a['foo'] = 100 print(a)OutputThis will give the output{'foo': 100, 'bar': 55}If you really want multiple values for a single key, then you should probably use a list to be associated with the key and add values to that list.
3K+ Views
You can first convert the json to a dict using json.loads and then convert it to a python tuple using dict.items(). You can parse JSON files using the json module in Python. This module parses the json and puts it in a dict. You can then get the values from this like a normal dict. For example, if you have a json with the following content −Example{ "id": "file", "value": "File", "popup": { "menuitem": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"}, ... Read More
1K+ Views
You can parse JSON files using the json module in Python. This module parses the json and puts it in a dict. You can then get the values from this like a normal dict. For example, if you have a json with the following content{ "id": "file", "value": "File", "popup": { "menuitem": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"}, {"value": "Close", "onclick": "CloseDoc()"} ] } }You can load it in your python program and loop over ... Read More
3K+ Views
If you have the exact key you want to find, then you can simply use the [] operator or get the function to get the value associated with this key. For example,Examplea = { 'foo': 45, 'bar': 22 } print(a['foo']) print(a.get('foo'))OutputThis will give the output:45 45ExampleIf you have a substring that you want to search in the dict, you can use substring search on the keys list and if you find it, use the value. For example,a = { 'foo': 45, 'bar': 22 } for key in a.keys(): if key.find('oo') > -1: print(a[key])OutputThis will give the output45
To Continue Learning Please Login
Login with Google