Found 10784 Articles for Python

What is the basic syntax to access Python Dictionary Elements?

mkotla
Updated on 05-Mar-2020 10:02:01

140 Views

You can access a dictionary value to a variable in Python using the access operator []. examplemy_dict = {    'foo': 42,'bar': 12.5 } new_var = my_dict['foo'] print(new_var)OutputThis will give the output −42You can also access the value using the get method on the dictionary. examplemy_dict = {    'foo': 42,'bar': 12.5 } new_var = my_dict.get('foo') print(new_var)OutputThis will give the output −42

Finding The Biggest Key In A Python Dictionary?

Samual Sam
Updated on 05-Mar-2020 07:17:57

2K+ Views

If you have a dict with string-integer mappings, you can use the max method on the dictionary's item pairs to get the largest value. exampled = {    'foo': 100,    'bar': 25,    'baz': 360 } print(max(k for k, v in d.items()))OutputThis will give the output −foofoo is largest in alphabetical order.

How expensive are Python dictionaries to handle?

Lakshmi Srinivas
Updated on 30-Jul-2019 22:30:22

158 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.

Do you think Python Dictionary is really Mutable?

karthikeya Boyini
Updated on 05-Mar-2020 07:13:52

177 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}

How can I convert Python dictionary to JavaScript hash table?

radhakrishna
Updated on 05-Mar-2020 07:13:01

1K+ 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

How to split Python dictionary into multiple keys, dividing the values equally?

Samual Sam
Updated on 30-Jul-2019 22:30:22

566 Views

Very use case specific: https://stackoverflow.com/questions/30447708/split-python-dictionary-into-multiple-keys-dividing-the-values-equally

Can you please explain Python dictionary memory usage?

Arjun Thakur
Updated on 17-Jun-2020 11:40:07

611 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.

How to optimize Python dictionary memory usage?

Samual Sam
Updated on 30-Jul-2019 22:30:22

540 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

How to check for redundant combinations in a Python dictionary?

Chandu yadav
Updated on 05-Mar-2020 07:09:45

97 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.

How to convert JSON data into a Python tuple?

Lakshmi Srinivas
Updated on 05-Mar-2020 07:07:37

4K+ 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

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