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1. Top results related to why do we need a dictionary in python

   • Why do we need str(f.read()) when reading a file in Python?

     Top Answer

     Answered Mar 23, 2017 · 1 votes

     Per the documentation, a file object's read method will return a string when the file is opened in text mode, or a bytes object in binary mode.

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     1/5

   • Why do we need to use __new__() when extending a immutable class in Python?

     Top Answer

     Answered Jun 21, 2015 · 3 votes

     If you do MyClass(1), then 1 is indeed passed as an argument to __init__. But __new__ is called before __init__, so 1 is first passed as an argument to __new__. The error you are seeing is because you didn't override __new__, so the inherited float.__new__ is being called, and it doesn't accept your extra argument. It never gets a chance to even try calling __init__, because it fails when trying to call __new__.

     This is explained in the documentation. As clearly stated there, the arguments you pass when instiating a class (e.g., the 1 in MyClass(1)) are passed to both __new__ and __init__, in that order.

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     2/5

   • Why do we Need Immutables in Python ?

     When a Novice steps into the Programming world and kicks off to learn about different concepts of it and yet eventually reaching to the Data Structures and Algorithms, learning and implementing them, but one or the other way he/she tends to read once and forget about the Immutable object.

     Mutable and Immutables exists in every programming language, yet one only tends to care about the mutable, like lists, queues, etc and take no or little notice of the immutables because at first impression it seems to be just an add-on and doesn’t seem to have any real-life problem-solving applications, and to debunk this idea, let us discuss the concept, need of it and Limitations.

     What are Immutable Objects?

     Mutability is a differentiating property of a data types in Python that makes a big contrast from the other data types, It tends to be an ability of data types to allow being modified after it is created, to which a value can be added as well as can be popped out of it. On the other hand, looking on the other side there are objects too that don’t...

     Check all answers on Geeksforgeeks

     3/5

   • Why do we Need Immutables in Python ?

     When a Novice steps into the Programming world and kicks off to learn about different concepts of it and yet eventually reaching to the Data Structures and Algorithms, learning and implementing them, but one or the other way he/she tends to read once and forget about the Immutable object.

     Mutable and Immutables exists in every programming language, yet one only tends to care about the mutable, like lists, queues, etc and take no or little notice of the immutables because at first impression it seems to be just an add-on and doesn’t seem to have any real-life problem-solving applications, and to debunk this idea, let us discuss the concept, need of it and Limitations.

     What are Immutable Objects?

     Mutability is a differentiating property of a data types in Python that makes a big contrast from the other data types, It tends to be an ability of data types to allow being modified after it is created, to which a value can be added as well as can be popped out of it. On the other hand, looking on the other side there are objects too that don’t...

     Check all answers on Geeksforgeeks

     4/5

   • Why do we need property in Python?

     Top Answer

     Answered Jun 14, 2015 · 4 votes

     You're right, you don't need properties to perform validation on setting an attribute, or to perform special behavior when doing attribute lookup. But properties are more readable and nicer to write. I'd stick to using __getattr__ and __setattr__ in cases where you want to dynamically access attributes (that is, you don't know what attributes you'll have at the time of class definition). Otherwise, use properties, as they are a very recognizable python idiom.

     In fact, in this case where you have two properties which are performing the same validation, I might use a descriptor:

     class NameDescriptor(object):- def __init__(self, key): self.key = key- def __get__(self, obj, objtype): return getattr(obj, self.key)- def __set__(self, obj, val): setattr(obj, self.key, val.capitalize())-class User(object):- firstname = NameDescriptor('_firstname') lastname = NameDescriptor('_lastname')- def __init__(self, first, last): self.firstname = first self.lastname = last-

     A demo of how this works:

     >>> user = User('steve', 'martin')>>> user.firstname'Steve'>>> user.firstname = 'dean'>>> user.firstname'Dean'-

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     5/5

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2. thispointer.com › what-is-a-dictionary-in-pythonWhat is a dictionary in python and why do we need it ...

   thispointer.com › what-is-a-dictionary-in-python

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   Apr 30, 2023 · Why do we need dictionaries? As a dictionary, keeps the elements in key-value mapping format and internally uses hashing for it; therefore, we can get a value from the dictionary by its key very quickly. In best cases, its complexity is O(1), whereas, in the worst case, its complexity can be O(n).

3. www.geeksforgeeks.org › python-dictionaryDictionaries in Python - GeeksforGeeks

   www.geeksforgeeks.org › python-dictionary

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   Apr 9, 2024 · Dictionaries in Python is a data structure, used to store values in key:value format. This makes it different from lists, tuples, and arrays as in a dictionary each key has an associated value. Note: As of Python version 3.7, dictionaries are ordered and can not contain duplicate keys. How to Create a Dictionary.

4. Videos

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     What is a Dictionary in Python and Why do we need it? Python Dictionary Tutorial #1

     May 24, 2023

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     Lec-23: Dictionary in Python 🐍 with Exs | Why accessing from Dictionary is fast | Python 4 Beginners

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     Python Tutorial for Beginners 5: Dictionaries - Working with Key-Value Pairs

     May 17, 2017

     1.5M Views

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5. python.land › python-data-types › dictionariesPython Dictionary: How To Create And Use, With Examples

   python.land › python-data-types › dictionaries

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   Jul 14, 2023 · 1 Creating a Python Dictionary; 2 Access and delete a key-value pair; 3 Overwrite dictionary entries; 4 Using try… except; 5 Valid dictionary values; 6 Valid dictionary keys; 7 More ways to create a Python dictionary; 8 Check if a key exists in a Python dictionary; 9 Getting the length of a Python dictionary; 10 Dictionary view objects; 11 ...

6. www.freecodecamp.org › news › python-dictionariesPython Dictionaries 101: A Detailed Visual Introduction

   www.freecodecamp.org › news › python-dictionaries

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   Dec 30, 2019 · Why they are important for your programming projects. The "anatomy" of a dictionary: keys, values, and key-value pairs. The specific rules that determine if a value can be a key. How to access, add, modify, and delete key-value pairs. How to check if a key is in a dictionary. What the length of a dictionary represents.

7. www.w3schools.com › python › python_dictionariesPython Dictionaries - W3Schools

   www.w3schools.com › python › python_dictionaries

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   Dictionaries are used to store data values in key:value pairs. A dictionary is a collection which is ordered*, changeable and do not allow duplicates. As of Python version 3.7, dictionaries are ordered. In Python 3.6 and earlier, dictionaries are unordered. Dictionaries are written with curly brackets, and have keys and values:

   Code sample

   thisdict ={

     "brand": "Ford",

     "model": "Mustang",

     "year": 1964

   }...

   See more on w3schools

8. www.programiz.com › python-programming › dictionaryPython Dictionary (With Examples) - Programiz

   www.programiz.com › python-programming › dictionary

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   A Python dictionary is a collection of items, similar to lists and tuples. However, unlike lists and tuples, each item in a dictionary is a key-value pair (consisting of a key and a value). Create a Dictionary. We create a dictionary by placing key: value pairs inside curly brackets {}, separated by commas. For example, # creating a dictionary .

9. stackabuse.com › python-dictionary-tutorialGuide to Dictionaries in Python - Stack Abuse

   stackabuse.com › python-dictionary-tutorial

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   Aug 31, 2023 · Dictionary comprehension in Python is a powerful mechanism enabling us to do much more than just create simple dictionaries. For example, you can also use it to create and access nested dictionaries: print (transpose) # Output: {0: {0: 1, 1: 4, 2: 7}, 1: {0: 2, 1: 5, 2: 8}, 2: {0: 3, 1: 6, 2: 9}}