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36
votes
2answers
4k views

How do I move away from the “for-loop” school of thought?

This is a rather conceptual question, but I was hoping I could get some good advice on this. A lot of the programming I do is with (NumPy) arrays; I often have to match items in two or more arrays ...
29
votes
11answers
7k views

How does the “Fourth Dimension” work with arrays?

Abstract: So, as I understand it (although I have a very limited understanding), there are three dimensions that we (usually) work with physically: The 1st would be represented by a line. The 2nd ...
7
votes
8answers
12k views

What is the difference between an Array and a Stack?

According to Wikipedia, a stack: is a last in, first out (LIFO) abstract data type and linear data structure. While an array: is a data structure consisting of a collection of elements ...
6
votes
4answers
57k views

Initializing char array with string

I don't remember how I got to the thread, but I was reading its replies and one of them states that you should never initialize a char[] with a string literal. My question: Is initializing a ...
6
votes
3answers
2k views

Ordered enumeration: IEnumerable or Array (in C#)?

Typical context: I make an extension method for a collection which considers that the elements are ordered. The function starts at the beginning, at index 0, and the order has significance. Examples: ...
6
votes
2answers
950 views

How to remove the boundary effects arising due to zero padding in scipy/numpy fft?

I have made a python code to smoothen a given signal using the Weierstrass transform, which is basically the convolution of a normalised gaussian with a signal. The code is as follows: #Importing ...
5
votes
2answers
9k 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 ...
5
votes
6answers
914 views

why are both index[array] and array[index] valid in C?

For example consider: int index = 3; int array[4] = {0, 1, 2, 3}; then both index[array] and array[index] are valid expressions, much like *(index + array) and *(array + index). In C arrays why is ...
5
votes
4answers
601 views

Why do arrays in Java not override equals()?

I was working with a HashSet the other day, which has this written in the spec: [add()] adds the specified element e to this set if this set contains no element e2 such that (e==null ? e2==null : ...
5
votes
1answer
164 views

At ping, why do we have to do array copying instead of passing on the source array that the client sent to us?

So I have been googling about this OpenSSL heart-bleed thing and somehow sees that it is caused by the heartbeat extension which requires client to ping the server to show its aliveness and it all ...
5
votes
2answers
329 views

Which design pattern is illustrated by inheriting IStructuralComparable interface?

We know that some design patterns are found so useful that they become features of the language itself. For instance, the interface IEnumerator which is implemented by Array object. This helps in ...
5
votes
2answers
678 views

Implementing non-fixed length array support in a compiler

I'm thinking of building a language for PIC microcontrollers. I want to be able to use non-fixed size arrays, like this: Declare the variable as int[] Wait for input from serial connection Make the ...
5
votes
3answers
355 views

Generating Deep Arrays: Shallow to Deep, Deep to Shallow or Bad idea?

I'm working on an array structure that will be used as the data source for a report template in a web app. The data comes from relatively complex SQL queries that return one or many rows as one ...
4
votes
5answers
567 views

What's the effect of this assignment (whatever the language)?

I think my book (Programming Languages: Principles and Paradigms) is wrong. a is a vector, assume a C-like language: b = 0; a[f(3)] = a[f(3)] + 1; int f(int n) { if(b == 0) { b = 1; ...
4
votes
4answers
483 views

Why can't C arrays have 0 length?

The C11 standard says the arrays, both sized and variable length "shall have a value greater than zero." What is the justification for not allowing a length of 0? Especially for variable length ...
4
votes
3answers
936 views

Lisp: Benefits of lists as code over arrays as code?

Question for lisp programmers: Lisp code is lisp data, usually lists. Is there an advantage to code being lists over code being arrays? Would macros be easier to write/faster to run? You can ...
4
votes
2answers
1k views

Array Multiplication and Division

I came across a question that (eventually) landed me wondering about array arithmetic. I'm thinking specifically in Ruby, but I think the concepts are language independent. So, addition and ...
4
votes
3answers
2k views

C Flexible Arrays: When did they become part of the standard?

I learned to program in C many years ago, and used C steadily for about 10 years. These days, I occasionally have to look at C code, because our Informix 4GL RDS customized runners also contain C ...
3
votes
6answers
941 views

Why isn't the line count in Visual Studio zero-based?

This just struck me as an oversight by Microsoft. Since arrays and other data-structures within the .NET framework begin from zero (zero-based) why don't we have a line 0 within the code view in ...
3
votes
3answers
604 views

Is there a way to add unique items to an array without doing a ton of comparisons?

Please bare with me, I want this to be as language agnostic as possible becuase of the languages I am working with (One of which is a language called PowerOn). However, most languanges support for ...
3
votes
2answers
773 views

Should the 12-String be in its own class and why?

This question is regarding a homework project in my first Java programming class (online program). The assignment is to create a "stringed instrument" class using (among other things) an array of ...
3
votes
2answers
803 views

CA1819: Properties should not return arrays. Does this happen only with arrays? If yes, why?

I have a question about CA1819 msdn performance warning. The rule is: Arrays returned by properties are not write-protected, even if the property is read-only. To keep the array tamper-proof, the ...
3
votes
4answers
2k 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 ...
3
votes
1answer
728 views

The array class in C# - Implementation questions

I am studying the Array class in C#. The following is the implementation of System.Array class: [SerializableAttribute] [ComVisibleAttribute(true)] public abstract class Array : ICloneable, IList, ...
3
votes
2answers
297 views

Data structure for grid with negative indeces

Sorry if this is an insultingly obvious concept, but it's something I haven't done before and I've been unable to find any material discussing the best way to approach it. I'm wondering what's the ...
3
votes
2answers
169 views

What would be the optimal way to solve a problem like this?

I have a problem where I have to change all the Xs in a 2D array into 0s, and I have to calculate the minimum steps (where a single step consists of changing an entire row or column) required to do ...
3
votes
1answer
50 views

Conveniently sorting and (binary?) searching an array of pairs of numbers?

So I have an array of distinct pairs of positive integers. That is, my array looks something like this (for instance): { (1,5) , (6,4), (5,3), (2,3), (2,4) } And my task is, for a given pair (a,b) ...
2
votes
3answers
1k views

Specific reasons to create own array class over using std::array?

What specific conditions or requirements should you create your own array over using std::array? Here is my background: I'm developing a small simple library that a small group of people will use ...
2
votes
6answers
390 views

Settle an Argument: String vs. Array?

True or False: A string is the same thing as an array. I had an interview the other day and the above question was asked. I said false, but the interviewer said it was actually true. I explained to ...
2
votes
3answers
798 views

Best way to choose random element from weighted list

I want to create a simple game. Every so often, a power up should appear. Right now the different kinds of power ups are stored in an array. However, not every power up should appear equally often: ...
2
votes
3answers
554 views

What are pros and cons of using temporary “references”?

In C and C++ (and I guess other languages that allow taking a "reference" to an array element or something similar), when you have an array like type, accessing individual elements of such an array ...
2
votes
3answers
248 views

What language has integrated “list insertion” as part of code *syntax*?

Many programming languages permit natural manipulation of strings, and some languages permit the manipulations of lists too. More often then not (always?), these operations are done as procedure ...
2
votes
4answers
1k views

How do you find the first common element in two arrays

The way I did it was to loop through each at the same time and add the current value to a separate set for each of the lists. Also, check if the current element is already in the other list's set. I ...
2
votes
1answer
243 views

Why does Java support brackets behind variables and even behind method signatures? [closed]

Java allows this: class X{ int i,j[]; // j is an array, i is not } and even worse, it allows this: class X{ int foo(String bar)[][][] // foo actually returns int[][][] { return null; } ...
2
votes
4answers
407 views

Algorithm design for comparing split times in a race

I need to determine the ranking of values in an array without altering their position, so that I can print the position of each split time next to the actual value of the split time in a table like ...
2
votes
1answer
150 views

Improving the running time of Breadth First Search and Adjacency List creation

We are given an array of integers where all elements are between 0-9. have to start from the 1st position and reach end in minimum no of moves such that we can from an index i move 1 position back and ...
2
votes
1answer
123 views

Accessing a private array when I have an extension method

I'm trying to make a number of data classes for my C#/XNA game, which would essentially be a wrapper around T[,]: public interface IGrid<T> where T : struct { Point Size { get; } T ...
2
votes
1answer
129 views

Handling Dynamic amount of Strings for persistent and runtime storage in an IOS App

Background I am dynamically building an FQL query statement and because of the nature of the app, I exclude FB family members, this is the base portion of the query and remains fairly static. The ...
1
vote
5answers
174 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 ...
1
vote
3answers
470 views

How do you read this line of code?

Forgive me for my poor English, me and my friend were doing school homework, suddenly he asked me to read this line of code ptr = &array[1][1][1] (ptr is a pointer to an integer). He said ...
1
vote
4answers
245 views

Is it considered bad practice to access a returned array by a key straight away?

I couldn't think of a good way to word the title, sorry. But what I mean is, is it considered bad practice to do: print get_array()[2] over: output=get_array() print output[2] (where get_array() ...
1
vote
1answer
162 views

What is the name of this array transformation?

Start with an array of arrays; in this case, they are different lengths in order to demonstrate the technique, but they do not have to be. [[1,2,3,4], [5,6,7], [8,9,10], [11,12,13,14,15]] At the ...
1
vote
3answers
71 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
2answers
255 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: ...
1
vote
3answers
329 views

Choice between 1-dimensional and 2-dimensional array

I'm implementing the Chessboard class to represent the chessboard. I've to implement the transformations (reflections and rotations) on the chess board possible. The possible transformations includes ...
1
vote
1answer
91 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 ...
1
vote
2answers
615 views

Should I create specific classes for JSON Objects or only use the container(Array/Dictionary) for accessing Data?

I'm using Foursquare to get a List of Restaurants nearby inside an iOS app. The Result is stored in an Array which consists of Dictionaries and regarding how deep the Data is, each Dictionary contains ...
1
vote
3answers
949 views

Arrays vs Objects in view template

I am wondering, in view templates, what would contribute to me choosing between using arrays or objects for getting things printed out in arrays {{$user->zip_code}} vs {{$user['zip_code']}} I'm ...
1
vote
4answers
201 views

Efficient way of evaluating an array of strings then add to an array in Ruby

I am looking for an efficient way of evaluating an array of strings against a series of rules and then adding them to another array. For example I have an array of strings: something a 1234 #gohere ...
1
vote
2answers
791 views

2D linked list vs. multidimensional array/vector

I hope that programmers is the correct stack exchange for this, as it is quite a concept based question. I'm working on a data structure in C++ that is a represents data in 3D space. The x-y plane is ...