An array is a systematic arrangement of similar objects, usually in rows and columns.

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0answers
9 views

need to find the index at p percent of the array length, and return all the values before that index point [migrated]

given an int[] x and a perentage p (0 - 100), find the smallest valued element y of x so that at least percentage p elements of x are less than or equal to y. I have code that sorts the array ...
-3
votes
1answer
89 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
4answers
196 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 ...
1
vote
1answer
68 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
votes
1answer
74 views

Should I add 1 to my unknown string size when I create a char array to hold it via malloc? [closed]

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! ...
4
votes
1answer
321 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 ...
-3
votes
1answer
120 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
71 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 ...
1
vote
4answers
76 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
77 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 ...
1
vote
1answer
316 views

What is the best approach to storing a multi-dimensional array with unknown bounds?

I'm trying to store content scraped from several lyric and chord websites into separate variables into either a multi-dimensional array, or into separate string arrays, but I've been stuck trying some ...
3
votes
5answers
313 views

What defines the dimensionality of an array?

I know that when we speak about an array having 1, 2, or 4 dimensions, we mean arrays like this: 1: [0] 2: [0,0] 3: [0,0,0] 4: [0,0,0,0] ... Is the first 'axis' of an array the only thing that ...
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 ...
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; ...
2
votes
2answers
192 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 ...
0
votes
3answers
22k views

2 Dimensional Arrays in C++

I started learning arrays in C++ and came over a little side note in the book talking about 2D arrays in breif. I tested it out and i was amazed that it could give the programmer the ability to store ...
-1
votes
1answer
57 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
162 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 ...
1
vote
2answers
264 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 ...
-1
votes
1answer
173 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 ...
2
votes
1answer
327 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
1answer
902 views

ruby-idiomatic hashes vs arrays

So I am still fairly new to ruby, though I have noticed that it is very hard to create 2d-array and that hashes seem to be more of the go to data structure than arrays. I was wondering why the Ruby ...
2
votes
3answers
298 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] = ...
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 ...
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votes
2answers
181 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 ...
30
votes
6answers
133k views

Is initializing a char[] with a string literal bad practice?

I was reading a thread titled "strlen vs sizeof" on CodeGuru, and one of the replies states that "it's anyways [sic] bad practice to initialie [sic] a char array with a string literal." Is this ...
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
53 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
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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
636 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 ...
1
vote
2answers
1k views

Why a hashtable? Why not just a non-hashed associative array?

I've been learning about using a hashtable to efficiently check for items in a list without looping through the whole thing, but there's one thing that I don't get: Why hashed keys? It seems like: ...
13
votes
1answer
433 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 ...
3
votes
2answers
96 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, ...
2
votes
2answers
143 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 ...
1
vote
2answers
221 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 ...
2
votes
2answers
323 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 ...
4
votes
3answers
539 views

@SuppressWarnings in generic array declaration

While doing a coding test, I ran into a problem where I need to initialize an array of generic type in Java. While trying to figure out how to do that, I looked at this Stack Overflow question and it ...
4
votes
5answers
6k views

Retrieving maximum value from a range in unsorted array

I have an unsorted array. I have queries in which I give a range and then the maximum value from that range has to returned. For example: array[]={23,17,9,45,78,2,4,6,90,1}; query(both inclusive): 2 ...
13
votes
2answers
34k views

Should I use a list or an array?

I'm working on a windows form to calculate UPC for item numbers. I successfully create one that will handle one item number/UPC at a time, now I want to expand and do it for multiple item ...
2
votes
4answers
3k views

How do you find the first common element in two arrays

How do you find the first common element in two arrays? My attempt: I looped through each at the same time and add the current value to a separate set for each of the lists. Also, check if the ...
3
votes
1answer
425 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
114 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 ...
3
votes
2answers
424 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
0answers
393 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
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 ...
-2
votes
2answers
423 views

Fortran 90 - How to create a coordinate system

So I need to code a simple program, and I need to define 2D coordinates? Is there any coordinate system I can use in Fortran? I was told it might have to be all in arrays? And if so, can anybody ...
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 ...
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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 ...