An array is a systematic arrangement of similar objects, usually in rows and columns.
1
vote
4answers
173 views
Readability & Performance: Is it better to allow the Java garbage collector to clear a datastructure?
I work with large HashMap's and ArrayLists. When not needing them to be in memory any longer, I use myArray.clear(); to free up the memory.
When my colleague saw that line, he changed it to myArray ...
-4
votes
1answer
61 views
pick new item from array every day
Let's say I have an array of any fixed length i.e. it could be 3, 5, 7 ... upto 30.
How can I generate an algorithm such that if I pick an item from the array, every single day, it should not pick ...
-1
votes
1answer
74 views
Should I add 1 to my unknown string size when I create a char array to hold it via malloc? [on hold]
When I have a string of unknown size and I create an char array to hold this string.
I do something like this:
#define LINE_END "\r\n"
int line_end_size = strlen(LINE_END);
char line[]="Hello! ...
-3
votes
1answer
118 views
Using System.out.println() with loops and arrays [closed]
Is there anyway I can create a loop for System.out.println("...") and reading in the values? For example I wish to do this:
System.out.println("Input the Executive's name: ");
String eName = ...
-5
votes
0answers
69 views
How to add entries to an ArrayList in another class?
I'm trying to create a list of Strings that user has saved as favourites. The Favourites are displayed in a class separate to the MainActivity in their own list, but the user is supposed to mark it as ...
0
votes
0answers
29 views
Realizing pagination for merged array from multiple data sources (APIs)
I'm improving a WordPress theme with PHP. The theme contains a gallery section which loads data from the Flickr API.
Now the client wants to display Flickr galleries as well as "local" galleries ...
-3
votes
1answer
65 views
How to compare and replace value from two object inside array?
Here i want to replace price in data1 to price from data2, and it updated if the id is same.
Is it possible to do that without nested loop?
var data1 = [{
"id": "56e641d4864e5b780bb992c6",
...
1
vote
1answer
67 views
How to combine N non-comparable arrays up to an output limit in a fair way?
Given N non-comparable arrays of different sizes, what is the best method to combine them into one output array?
Since the input arrays are non-comparable, a metric is needed to represent how ...
1
vote
4answers
75 views
Obtaining lists from an array
Let's say my array contains integers. I'd like to create lists, so that every list contains indexes where a particular value occured in the array. For instance, if the array was 5,0,3,5,2,5,3, we ...
1
vote
0answers
74 views
Why my greedy algorithm not working for merge stone problem
Merge Stone Problem:
You have n piles of stones in a line.
For example, [4, 1, 2] means 3 piles of stone, the first pile has 4 stones, the second pile has 1 stone, and so on.
You task is to merge ...
0
votes
1answer
118 views
Is there ever a reason to use variable variables in PHP rather than an array? [closed]
Is there any situation where an array is not suitable but a variable variable is? I cannot think of one or find one on any Stack Programmer Q&A.
<?php
$foo = array();
for($i = 0;$i < 3; ...
0
votes
1answer
133 views
How to save tuplas values, to later search on it
Scenario
I have some values of the type : (Name - Email)
From this couples of data, I have to set a ArrayList of "Name" values,something like: |Name1|Name2| --- |NameN| to set a Spinner. (Ordered ...
2
votes
2answers
190 views
Merge sort and O(n log n) mystery
I read every explanation here but still not convinced. I think mergesort is n * n and I know I am wrong but not sure where. Here is what I think:
Suppose we are sorting 8 elements and this is the ...
-1
votes
1answer
56 views
(Multidimensional array in C) How to make my output in a vertical position rather than in horizontal when the size of the array is n[3][4] [closed]
I would like to have some help.
I must find a way that the output must be:
A B C
90 60 80
50 100 70
100 20 100
10 50 75
Because the previous output is:
A 90 50 100 10
B 60 100 ...
5
votes
2answers
133 views
How to store ordered information in a Relational Database
I am trying to understand how to properly store ordered information in a relational database.
An example:
Say I have a Playlist, consisting of Songs. Inside my Relational Database, I have a table of ...
4
votes
1answer
320 views
Why is Array.prototype designed to be a fully functional array?
In the below visualisation,
There are two array objects(cars & bikes) that are created with below syntax,
var cars = new Array("Saab", "Volvo", "BMW");
var bikes = ["Honda", "Yamaha"];
whose ...
-1
votes
1answer
171 views
eradicating the array = loop mindset [closed]
I have noticed a common issue in code reviews, that takes this form:
// "arr" is an array
for (i = 0; i < arr.length; ++i) {
if (i == 3) {
// do something with arr[i]
}
if (i ...
10
votes
1answer
2k views
PHP: when to use arrays, and when to use objects for mostly-data-storing code constructs?
PHP is a mixed paradigm language, allowing to use and return non-object data types, such as arrays. I pose a question to try to clarify some guidelines for selection of arrays vs objects when deciding ...
-1
votes
2answers
180 views
3D array updating in C# [closed]
I'm curious because I have read that once an array is declared it can not be changed. Maybe if I lay out my thoughts.
Say, I have a cube with dimensions 5x5x5 and I have a viewport that can rotate ...
21
votes
5answers
7k views
What's the use of .Any() in a C# List<>?
I've been discussing this with colleagues, and we couldn't figure out what the use is of .Any for any given List<>, in C#.
You can check the validity of an element in the array like the ...
2
votes
3answers
292 views
Is it a good idea to modify the array keys in foreach
Some times I need to modify an array key for example something like:
$temp = array();
foreach($arrayIWantToModify as $key => $value) {
if($value % 2) == 0) {
$temp['odd_' . $key] = ...
0
votes
0answers
40 views
Is it better to store integer data or array references in a javascript visualization?
Say I have a tree that I'd like to visualize with d3. Nodes have various attributes produced by the d3 library, attributes like an index and position variables. Now, I could add more attributes to ...
0
votes
0answers
52 views
Microcontroller oLED Display Buffering Optimizations or Alternatives For Speed?
I'm developing a UI/Layout for a 128 x 64 oLED Monochrome Pixel Display. I've got a small netMF microcontroller driving the display via SPI at 40mhz.
I'm using some basic methods, like these here, to ...
1
vote
0answers
263 views
Why is deep plucking a bad idea?
Both underscore and lodash refuse to implement deep plucking, despite many requests from users and gists or modules that implement the feature.
...
3
votes
1answer
616 views
sort multidimensional array recursively - is this reasonable
In a nutshell, I needed to traverse any number of dimensions of a multidimensional array (or not) and I wanted the process to be as predictable as possible (in order to proliferate the pattern ...
3
votes
2answers
95 views
Reducing a sequence of array modification operations (insert, sort, replace, remove)
Given a plain array of values, e.g.
["Apple", "Orange", "Banana", "Strawberry"]
and a list of operations from the set of [insert, delete, sort and replace], e.g.
[
{cmd: "insert", index: 2, ...
13
votes
1answer
431 views
Why using sizeof of type to calculate the number of elements in an array is considered inferior to using sizeof of an element?
I'm reading "King K.N's C programming" and I'm reading the following statement:
We discussed using the expression sizeof(a)/sizeof(a[0]) to calculate the number of elements in an array. The ...
2
votes
2answers
141 views
How to create a 2D array at runtime in Ada? [closed]
In Ada programming, What is a best practice way to create a 2D array of a size that is specified by the user?
I'm teaching myself Ada for work (after many years of C programming), and I'm having ...
2
votes
2answers
320 views
Find the maximum number of pairs of numbers that are in a range, between two arrays
Lets say I have two arrays A and B
A = {1,2,3}
B = {12,11,67}
and have max sum value S = 10
How many maximum number of unique pairs can be formed between the two arrays who's sum is less than or ...
2
votes
1answer
324 views
Beginners C# question about Array.Reverse
I am sitting through a very well-explained and thorough video tutorial series, using Visual Studio 2012 as my developing environment.
Anyway, one thing that is hard to figure out is this. Say you ...
1
vote
2answers
219 views
What is the algorithmic time complexity of this program?
I wrote a simple program in java to create and maintain Dynamic Arrays:
public class DynamicArrays {
private Integer[] input = new Integer[1];
private Integer length = 0;
private Integer ...
3
votes
1answer
422 views
Why is iterating through List<T> more expensive than iterating through Array in .NET?
According to the answers in this post, List<T> is backed by an Array. According to this article, list iteration is considerably slower than array iteration.
If Lists are arrays 'under the ...
0
votes
0answers
113 views
GMP Core Dump while using mpz_clear in C
I'm working on a prime factorization program written in C using the GMP library through cygwin. The algorithm that I have now works fine, but has memory leaks from not using the mpz_clear function on ...
1
vote
1answer
118 views
What is VLA and how it is implemented?
Most languages does support variable length arrays on the heap but I've heard that those can be stored on the stack too. I'm curios what languages support this construct, some examples and how are ...
1
vote
0answers
385 views
How to loop through array bidimensional in diagonal according to a position in degrees
The title could be no self-explanatory enough but I need some conceptual help in order to implement a solution to go through an array:
I'm developing a program to calculate the "most shadepath" route ...
1
vote
2answers
263 views
Non-fixed-size Fenwick Tree implementation
I'm planning to implement a non-fixed-size Fenwick tree. That is, a Fenwick tree that allows interleaving range queries with adding/removing elements.
All implementations and samples I've seen so far ...
3
votes
2answers
418 views
How to draw rectangles for 2D arrays
I have an 2D boolean array that looks like this:
[0][0][0][0][0][0][0][0][0][0]
[0][0][0][0][0][0][0][0][0][0]
[0][0][0][0][0][0][0][0][0][0]
[0][0][0][1][1][1][0][0][0][0]
...
1
vote
1answer
97 views
Why use atomic vectors or matrices in R at all?
In reading Hadley Wickham's Advanced R I learned about the difference between atomic vectors and lists; and matrices/arrays and dataframes. This is something I hadn't really appreciated before, and ...
-2
votes
3answers
2k views
How to store integer array in mysql database [closed]
I am making a college attendence system so i need to store attendence of thousands of students. if I go for 1 column for each day then it will take 12*30 almost 360 column for a year. So I want to ...
3
votes
3answers
485 views
How do you iterate through an array and delete an element?
I have an array and I can iterate through it. I know that it is impossible to change the size of an array; however, how do I take out a certain element that I not want in the array anymore?
Example: ...
1
vote
2answers
59 views
Function that would output all distinct values in an array
I want to create a function that outputs the distinct values in a given array. For example, in the following sequence 2 2 1 1 5 2 , the distinct digits are 2 1 5. What I've done till now is:
void ...
1
vote
3answers
447 views
Addition or deletion of elements of a dynamic array
Is there any consensus among programmers (or a common convention) on the "right way" to deal with the addition or deletion of one or more elements of a dynamic (mutable) array at runtime while ...
1
vote
1answer
45 views
Expectations on input / output of array dimensions and approaches to implement support for variable dimensions input arrays
Preamble
As we are vectorising our colour API, we are changing the accepted input types for most of our functions. We would be keen on keeping backward compatibility with the existing code.
Let's ...
0
votes
1answer
116 views
Two dimensional matrix-like data type using lists and/or mutable lists
I am trying to think of an implementation of a two dimensional matrix-like data type.
Normally I would take an array of arrays but I'm bound to a relatively low language level which only provides ...
1
vote
0answers
184 views
Should I use enums or arrays for a dynamic data source?
I've inherited an iOS project that uses NS_Enum to store the number of rows and sections in a UITableView At the moment, the UITableView is static; no rows are being added to it. However, that is what ...
0
votes
2answers
325 views
Check all “lines” in an array?
I have a 3D array with booleans and I need to check if there are "lines" that all contain true or false. With lines I mean horizontally, vertically and diagonally within the array. However I only need ...
-3
votes
1answer
53 views
How can this allocation of bi-dimensional arrays work? [closed]
I was seeing this post on StackOverflow and saw a new way (at least for me) to define a two dimensional array of 5x5, it works well, but I feel I don't understand what is going on in the background.
...
1
vote
3answers
214 views
Question about multidimensional arrays
I was wondering something about the multidimensional arrays and then I got a doubt about a concept, specifically about their representation on memory.
For example, an array can be defined as follows.
...
1
vote
1answer
78 views
Is it possible to quickly change an array declared on the stack to one declared on the heap
I have about 5000 lines of code which manipulates a large array in C++. The problem is that when I try to make the array even larger i.e. A[10000][10000], the gcc compiler throws me a segmentation ...
0
votes
3answers
898 views
Using action array vs Switch Case [closed]
I have an occasion of code in which I will draw a different set of buttons in a screen (depending on the number of the buttons).
One thought (and my current implementation) is to use an action array ...
