immutability Questions

3

Solved

Conventional way of dealing with optional list arguments is the following: def func(list_of_vals = None): if list_of_vals is None: list_of_vals = [] ... I wounder if the following (shorter) v...
Climax asked 28/10, 2016 at 21:36

10

It is possible to create a DeepReadonly type like this: type DeepReadonly<T> = { readonly [P in keyof T]: DeepReadonly<T[P]>; }; interface A { B: { C: number; }; D: { E: number; }[...
Inconsequent asked 26/1, 2017 at 17:23

2

Solved

Assume that I have the following mutable class: class Foo { constructor(public bar: any) { } } I can define readonly instances of this class like so: const foo: Readonly<Foo> = new Foo(1...
Insusceptible asked 27/5, 2020 at 7:59

6

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Why should objects in Redux be immutable? I know that some frameworks such as Angular2 will use onPush and can take advantage of immutability to compare states of views for faster rendering, but I ...
Proteus asked 23/1, 2016 at 2:1

6

I have several classes that are immutable once their initial values are set. Eric Lippert calls this write-once immutability. Implementing write-once immutability in C# usually means setting the i...
Nw asked 18/8, 2009 at 14:35

3

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I've been looking at the readonly type in typescript. Sadly, it does not work as i hope it would. For instance, see the code below: interface User{ firstName: string; lastName: string; } const ...
Inimitable asked 21/11, 2018 at 13:17

14

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A frozen set is a frozenset. A frozen list could be a tuple. What would a frozen dict be? An immutable, hashable dict. I guess it could be something like collections.namedtuple, but that is m...
Fahlband asked 24/4, 2010 at 7:19

4

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I've done some searching and found that JavaScript objects can be frozen or sealed, meaning that they cannot be modified or have new properties added to them, respectively. I understand what these ...
Masters asked 9/12, 2022 at 0:49

2

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Kotlin has a const-keyword. But I don't think constants in kotlin are what I think they are. It seems to very different to const in C++. It seems to me that its is only available for static members...
Schoolgirl asked 24/8, 2019 at 7:45

2

I'm new to ngrx (and never used redux) and am trying to make sense of it all - especially whether you need deep copies of the state. Here's what I've learned so far and what still confuses me (furt...
Quilmes asked 3/1, 2020 at 11:34

16

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I seem to be having issues pushing data into a state array. I am trying to achieve it this way: this.setState({ myArray: this.state.myArray.push('new value') }) But I believe this is incorrect w...
Foamflower asked 25/5, 2016 at 11:8

13

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import copy a = "deepak" b = 1, 2, 3, 4 c = [1, 2, 3, 4] d = {1: 10, 2: 20, 3: 30} a1 = copy.copy(a) b1 = copy.copy(b) c1 = copy.copy(c) d1 = copy.copy(d) print("immutable - id(a)==id(a1)", id(...

13

Solved

import copy a = "deepak" b = 1, 2, 3, 4 c = [1, 2, 3, 4] d = {1: 10, 2: 20, 3: 30} a1 = copy.copy(a) b1 = copy.copy(b) c1 = copy.copy(c) d1 = copy.copy(d) print("immutable - id(a)==id(a1)", id(...
Renounce asked 22/6, 2013 at 2:15

13

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import copy a = "deepak" b = 1, 2, 3, 4 c = [1, 2, 3, 4] d = {1: 10, 2: 20, 3: 30} a1 = copy.copy(a) b1 = copy.copy(b) c1 = copy.copy(c) d1 = copy.copy(d) print("immutable - id(a)==id(a1)", id(...

14

It is not clear to me when anyone would need to use Object.freeze in JavaScript. MDN and MSDN don't give real life examples when it is useful. I get it that an attempt to change such an object at r...
Insurer asked 9/2, 2013 at 20:35

4

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I need an immutable list where I can get derive a second immutable list preserving all elements of the previous list plus an additional element in Java (without additional libraries). Note: This q...
Charters asked 21/7, 2021 at 21:53

14

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I am currently working on React JS and React Native frameworks. On the half way road I came across Immutability or the Immutable-JS library, when I was reading about Facebook's Flux and Redux imple...

6

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What tools or libraries exists for Java that will take an interface only with accessor method definitions and automatically generate an immutable object class and also a "builder" class for increme...
Monitory asked 6/2, 2013 at 9:43

20

I'm confused on what an immutable type is. I know the float object is considered to be immutable, with this type of example from my book: class RoundFloat(float): def __new__(cls, val): return f...
Joletta asked 8/11, 2011 at 19:41

1

Structs are immutable meaning that they can't change. I must clearly misunderstand this whole concept as it seems that sometimes I do get to change the struct, and othertimes I don't. Conside...
Warrigal asked 26/12, 2023 at 21:34

12

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Just curious: In Kotlin, I would love to get some val that can be initialized by lazy, but with a parameter. That's because I need something that's created very late in order to initialize it. Spe...

27

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I'm trying to remove specific characters from a string using Python. This is the code I'm using right now. Unfortunately, it appears to do nothing to the string. for char in line: if char in &quot...
Comparison asked 15/10, 2010 at 3:46

9

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I would like to write something like this: var d = new ImmutableDictionary<string, int> { { "a", 1 }, { "b", 2 } }; (using ImmutableDictionary from System.Collections.Immutable). It seems ...
Trying asked 4/6, 2014 at 9:22

5

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A few times, I've run into the scenario where an accessor method is needed for both mutable and immutable references. For ~3 lines it isn't a problem to duplicate the logic, but when the logic get...
Alembic asked 3/1, 2017 at 4:40

9

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Does python have immutable lists? Suppose I wish to have the functionality of an ordered collection of elements, but which I want to guarantee will not change, how can this be implemented? Lists a...
Suomi asked 21/6, 2012 at 16:15

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