Questions tagged [array]
An array is a systematic arrangement of similar objects, usually in rows and columns.
223 questions
16
votes
10
answers
5k
views
C#'s Aversion to Array
I have noticed in documentation, looking at open-source code bases, and just a general sense in the industry that C# developers largely prefer to use List<> or IEnumerable<> over simple ...
- 423
1
vote
1
answer
84
views
Is there an idiom for specifying axes and dimensions of array(-like) parameters? [closed]
Many programming languages have functions which take a parameter which is a potentially-multi-dimensional array, where the number of axes and the dimension in each axis is not specified in code. This ...
- 2,808
0
votes
1
answer
242
views
Elegant way in C to store many parameters with default value and current value in embedded flash
I'm programming an embedded system that has a number of user configurable parameters, which are stored in flash memory. I have to store a default value for each parameter as well as the user settings. ...
- 175
0
votes
1
answer
625
views
Array structure for nested grouping (JavaScript)
I am currently struggling with how to solve nested grouping of data.
The initial structure is given and my grouped structure below as well as my approach can be adjusted.
My idea was to have the array ...
- 101
27
votes
6
answers
28k
views
How can Rust be "safer" and "faster" than C++ at the same time?
I have been told that Rust is both safer and faster than C++. If that is true, how can that be even possible? I mean, a safer language means that more code is written inside the compiler, right? More ...
- 403
-2
votes
3
answers
158
views
What are the pros and cons of different combinations of objects and arrays for data storing?
From the article JavaScript 2D Array – Two Dimensional Arrays in JS, I see one way to store data is to put all properties of each element into one array:
let dataRepresentation1 = [
['John Doe', ...
- 335
4
votes
4
answers
1k
views
When should tuples be used as an argument instead of an array?
I hope this isn't too off-topic/opinion-based, I'm new here.
I want to pass three elements of the same type into a function. The three elements are unique cards of a deck of cards, so they're not ...
- 59
0
votes
4
answers
2k
views
What prevents Java from having immutable primitive arrays?
Java never had immutable primitive arrays. However Java does have an immutable List or Map or other collection classes and of course final primitive fields and variables. In Java if you try to make an ...
- 1,219
7
votes
2
answers
4k
views
Why does C not support direct array assignment?
In C you cannot assign arrays directly.
int array[4] = {1, 2, 3, 4};
int array_prime[4] = array; // Error
At first I thought this might because the C facilities were supposed to be implementable with ...
- 1,219
0
votes
3
answers
163
views
How multiple type lists are stored in memory?
Arrays are stored in a linear fashion, with memory cells of fixed size for each element. To have fixed sized memory cells Arrays should be homogenious. So in Arrays we get an Nth element by skipping ...
- 39
4
votes
2
answers
2k
views
Multidimensional vs nested arrays
A seemingly basic question here.
Is there anything you can do with multidimensional arrays that you can't do with nested arrays?
Many languages have been designed with both facilities and syntactical ...
- 12.6k
0
votes
0
answers
63
views
JavaScript: My logic traversing multi-dimensional arrays
Consider the following:
Let's say below is the multi-dimensional, and you are given the starting point of [2, 2].
const WORLD = [
['P', 'P', 'P', 'C', 'P'],
['P', 'M', 'P', 'C', 'P'],
...
0
votes
0
answers
166
views
Best choice for a holding large number of objects in java
I have a set of array, containing a large number of objects (products), which has lately grown so large, searching in it takes about a minute, which is considered too long, since one search is ...
- 101
2
votes
2
answers
3k
views
JS - two array filters vs. one forEach?
I've had a question for a while. I know that the Array prototype method filter is generally preferred over forEach, and I believe it is typically faster at the job as well.
But what about if I have ...
- 129
2
votes
1
answer
2k
views
Do C++ compilers optimize/pack small data types (e.g. boolean values)?
This occurred to me when looking at stencil computations in numpy. This python library compiles compute-intensive components, so I believe that it's a valid example. Here making selections on an array ...
- 131
-2
votes
2
answers
1k
views
Comparing and replacing values in an array [closed]
I am currently working on a program that replaces the value in an array if the value next to it is the same as the current value. So If the array is [0,0,0,1,0,1,0], when the program runs it'll turn ...
- 13
4
votes
2
answers
1k
views
Arrays vs Maps for listing items that have a unique id
I've been finding that for a lot of code I've been writing recently, it naively might look like this:
Array approach:
const options = [
{
id: 'red',
label: 'Red',
data: '#f00'
...
- 2,769
8
votes
8
answers
9k
views
What is the difference between an index and an offset?
I am looking to understand the difference between the words index and offset.
I have never seen "offset" in reference to lists/arrays/etc in programming. I have only seen index.
To me, these ...
0
votes
1
answer
136
views
how to store the data for function f(time,length)
I have a function which has discrete time step ,discrete length from origin . These two give height of the function. For example at time 1.2sec , and length 5.5cm from origin height is 10cm. The step ...
- 19
-4
votes
1
answer
448
views
A good metaphor for "lists" (arrays)? [closed]
When teaching students Python lists (which are more like arrays, not linked-lists) I'd like to use metaphor of list being a collection of boxes put in row.
But this doesn't work well:
indexes are ...
- 93
8
votes
2
answers
7k
views
Is there a sensible way to sort coordinates?
Sorting is generally used to solve problems where distance between elements matters. A sorted list/array has the convenient property that the smaller the difference between the indices of any two ...
- 1,179
0
votes
3
answers
1k
views
How to guarantee an ID is unique in a non-UUID set of values?
I would like to have IDs of different sizes from the alphabet 0-9. So I have 5-length IDs as in 10000 or 13531, etc.. I have 10, 15, 20, up to 39 digit strings (the size of a UUID). I would like to ...
- 2,757
-2
votes
1
answer
129
views
Are jagged arrays lvalue or not?
When I was study lvalue i see that
C expression can be lvalue if a subscript ([]) expression that does not evaluate to an array.
(from
https://docs.microsoft.com/en-us/cpp/c-language/l-value-and-r-...
- 113
3
votes
1
answer
432
views
What is the expected performance of While loops using `array.pop()` assignment vs other methods
Recently I was asked to refactor some code that leverages JavaScript's array.reduce() method because other developers felt the code hard to read. While doing this I decided to play around with some ...
- 149
2
votes
2
answers
764
views
sizeof(a)/sizeof(a[0]) vs sizeof(a)/sizeof(t) where t is type in C from K.N.King
I'm trying to understand why sizeof(a)/sizeof(t) is inferior for getting the length of an array to sizeof(a)/sizeof(a[0]) if just as it's possible to have different types, my elements could also be of ...
- 41
-2
votes
1
answer
3k
views
Generate large Excel files and response from API
I need to generate a large Excel file (something around 50 megs) and send response to another API which will provide it to the front end for a download option.
My question is if it will be better to ...
- 389
1
vote
1
answer
515
views
How should I approach the comparison of two BMP images?
I am currently writing a Python program that retrieves the pixels from two BMP files and finds the percent difference between them (without using the Pillow library for the purpose of learning). I can ...
- 23
-2
votes
1
answer
3k
views
C# is fantastic, if only List 'd respect Remove&Return [closed]
In the domain of system-modeling (e, systemVerilog, matlab, phyton), lists are obsoleting arrays, stacks and queues(*) altogether. Other domains that use python, perl and ruby have that same mindset, ...
- 57
1
vote
3
answers
555
views
Are 'array elements' and 'array values' the same?
Array := {"title": "Book Title", "author": "John Doe"}
Some people use the following terminology:
title and author are keys.
Book Title and John Doe are values.
"title": "Book Title" and "author": "...
- 501
-1
votes
1
answer
114
views
Algorithm that maps consecutive whole numbers to sets of numbers
Where would I begin if I wanted to develop an algorithm that maps consecutive whole numbers to a long list of unique sets of whole numbers. For example:
0 = {0, 0, 0}
1 = {0, 0, 1}
2 = {0, 0, 2} ...
- 111
1
vote
1
answer
69
views
Determine array of objects collective identity and be able to inspect it
I have an array of objects and I'm trying to see, through each request, whether or not a new member appeared in my collection.
The way I currently do it is, I require each member of the collection to ...
- 657
1
vote
3
answers
3k
views
Does the gcc optimize out local arrays the same way it would optimize out a local variable?
If I write this code in a function:
void func(void)
{
int x = 0;
int y = 3724832+x;
}
It would (probably) optimize the variable y out because it isn't being used. Even if I'm wrong about this ...
user340139
1
vote
1
answer
677
views
PHP: simple class for storing read-only data structure, array alternative
I need to share some associative data between different parts of my application with two requirements:
immutability (so read-only)
safety against mispelling or unavailable index inside the data
mixed ...
- 111
2
votes
2
answers
104
views
At what size array in Swift would you consider switching to CoreData?
I've developed a reading tracking app in Swift and for simplicity's sake I used arrays for my model. It stores some data about the books a user reads and a small image of the cover. I save them to ...
- 31
1
vote
0
answers
43
views
is it better to have tracking fields that are maintained separately for arrays? [duplicate]
I wasn't sure exactly how to word this question, but basically, I have a struct stNeuralLayers (for a neural network I'm playing around with) with fields that are matrices (such as a double[,] ...
- 151
0
votes
2
answers
519
views
Should execution continue if array is empty?
Just a general programming best practices question.
If I have a function like that takes in an array of items and the function then calls a series of other functions which filter and act on the items ...
- 11
2
votes
1
answer
2k
views
How should I define hardcoded strings with some variable parts? Reuse more characters? Or keep the whole sentence?
for example, sometimes I need to define a hardcoded string with some variable parts, I often have trouble to choose the style:
style 1 : reuse every characters when possible
showMessage(num){
let ...
- 5,760
2
votes
2
answers
548
views
Should I use Array or Set if both can be used to finish my task?
for example, Suppose I have a 2d array:
let filterArr=[
[1,1,0,1,1],
[0,1,1,1,0],
[1,1,0,1,0]
];
I want to find and store the index of column that all are 1, i.e.:position 1 and 3, and the ...
- 5,760
0
votes
1
answer
169
views
For arrays, should I use the first position to store the selected element, instead of variable like "selectedIndex", if possible?
For example, I have a toggle button, which would show the current selected element, and would show next element when it is clicked, and it can loop back to first element. I have 2 ways to store the ...
- 5,760
2
votes
2
answers
202
views
Should special case be inside or outside the for loop here?
For example, suppose I have 2 arrays:
let arr1=[5,2,1];
let arr2=["abcde","ab","a"];
my work is simple : to check if length of strings in arr2 are larger than corresponding element with same index in ...
- 5,760
3
votes
2
answers
141
views
Should I move tasks which is just for a specific element only out of for loop?
For example, I have a for loop, which element 0 has additional function to run compared with other elements, my question is, should the additional function be:
1.place inside for loop
for(int i=0;i&...
- 5,760
2
votes
3
answers
4k
views
How do I put objects of different types derived from a common base in the same array? [closed]
I have two classes called Player and Enemy both inheriting from a class called GameObject, how do I store them both in an array of type GameObject while still keeping their own unique information?
I ...
3
votes
1
answer
159
views
Array rotation algorithm
I'm developing an application which sends quotes to clients via email.
Since quotes are obtained from various resources (per each client) they end up in a single array which is then used as a source ...
- 201
-1
votes
2
answers
1k
views
How does a dynamic array access work?
In C if i declare
int x[4]
Which tells me its an integer array with each array element size fixed of size 4.
So after initialization when I access x[3] : address of array +element size which is 2 * ...
- 11
1
vote
2
answers
178
views
Linked-list iteration patterns
If you have a linked-list, where the items are not necessarily close to each other in memory, wondering if it is (in general) better/worse/no difference to do the following.
Say you want to iterate ...
- 2,757
3
votes
1
answer
355
views
What is best practice for handling mapping arbitrary depth in arrays?
I have a set of data:
id | name | parentid
------------------------
1 | parent | 0
2 | child | 1
3 | child | 1
4 | parent | 0
5 | child | 4
6 | subchild | 5
7 | child | 4
...
- 241
4
votes
2
answers
6k
views
How exactly indexing works in arrays?
I only know that index is faster but don't know why is it faster.
Suppose I have an array int[] a = {2,3,6,7}. Then I will try to find the element at a[3] and the speed of this will be O(1). Why? How ...
- 151
12
votes
2
answers
2k
views
How did the custom of using square brackets for array elements develop?
Many programming language use the syntax a[i] to refer to the i'th element of an array, sequence, or vector a - specifically, C and Pascal (from the late 1960s and early 1970s) do this. On the other ...
- 2,808
1
vote
2
answers
665
views
Are there any use cases for List when Deques and Arrays are available?
I've been thinking about this over the past few weeks, and I've come up with no good arguments. My perspective is from Java, but if anyone has any language-specific cases outside of this language, I'...
- 229
3
votes
4
answers
137
views
Store csv data as rows or columns in view of the needed processing?
Assume I have some data a csv-Files like
ObjectName, PropertyA, PropertyB, PropertyC
"Name1", 3, 1, 4
"Name2", 1, 5, 9
"Name3", 2, 6, 5
...
and a typical question I want to answer would be
For ...
