Questions tagged [loops]
A **loop** is a sequence of statements which is specified once but which may be carried out several times in succession.
154 questions
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Should I separate special cases from for loop deliberately, or let a for loop handles special cases naturally?
Suppose I need to find the last selected index of options according to last selected contents, eg: options : A,B,C,D,E ,last selected option: C, so the last selected index is 2.
There is a special ...
- 2,659
3
votes
4
answers
399
views
Reducing cyclomatic complexity of a state machine
I have a function (written in Python) that processes a loosely structured log file.
The log file would have begin-end markers for different sections, with each section describing different things (e.g....
-3
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1
answer
85
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Declarative name for function with multi-purpose-loop from broken-up monolithic function [closed]
I'm currently in the process of reworking a monolithic function.
My first step is finding blocks of code that can be extracted into their own "sub"-methods for ease of readability & ...
- 97
2
votes
2
answers
143
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Using the word "loop" as a subject in a sentence [closed]
I would like to explain the following code to my colleagues:
for options in [{Option.NO_CUTOFFS}, {}, {Option.HEURISTIC}]:
...
The following sentence is kind of awkward:
This loop loops on the ...
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Loop pattern for batch data processing
When processing data sets in batches I usually can think of the following three implementations.
Which one do you consider better than the other and why?
Notes:
The implementation is in C# but the ...
- 115
1
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2
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218
views
Make infinite loop handleable via delay?
I have a Node.js micro-service architecture-based back-end. Services communicate with each other via PubSub. E.g. upon a request to service A, service A messages either service B or service C via ...
- 255
4
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2
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140
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Separation of data retrieval and processing in loops?
Often I need to get some data and process it in some way. For example getting a list of customers from an API and assemble some summary data on them. As an example, getting :
api_result = api.request(...
- 1,561
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85
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Explicit expression of a counter
Consider the following pseudo-code:
cont = 0
for g = 1,...,m
for h = g,...,m
cont = cont + 1
end for
end for
I'm searching for the explicit map that returns cont in ...
- 111
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answer
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How do I manage multiple nested for-loops without using multiple variables?
If I have code that looks like this:
int i;
void functionA (){
for (i=0; i<10; i++){
functionB();
}
}
void functionB (){
for (i=0; i<20; i++){
doSomething();
}
}
...
- 107
1
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2
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Calling recursive method in a loop - Backtracking
I'm confused about a matter that I've been unable to figure out. I'm doing some leetcode problems. In backtracking problems, sometimes we use loop within our recursive method to call the recursion but ...
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Declaring that a function never returns
If I have a function that never returns (it contains an infinite loop) how do I declare/communicate that it will never return to the user of the function?
The user does not see the source code, only ...
- 489
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5
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529
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How to deail with a hypothetical situation in which a pub/sub cycle gets into an unending recursive loop?
Let me explain what I mean. Imagine A subs to event b. In such case A pubs event a. B subs to event a. In this case B subs b. This is a full-blown circle. How does a pub/sub cycle deal with such ...
- 27
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votes
1
answer
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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
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What are use cases of using optional for loop statements?
I don't think any of them are good practice. In addition to that they make the code longer.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for
Optional initialization
...
- 219
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Is there any formula or trick to count how many times a statement inside a nested loop gets executed?
I am modifying a software which is for trash collection. While reading the code, I asked myself is there any formula or trick to quickly calculate the number of time the statement gets executed inside ...
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While loop definition in python
My question is about a use of while loops that seems very abstract to me. I understand a while loop like the first one (one which has a clearly defined statement):
num = 1
while num<1:
...
4
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2
answers
511
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How to avoid duplication in a for loop when "initialization step" is identical to "update step"?
I often find a situation where I need to write duplicate codes in a for loop, where the "init step" to identical to the "update step":
// duplicate `next()`
for (let x = next(); p(x); x = next()) {
...
- 266
-2
votes
1
answer
313
views
Is there a way to recreate the code behind the for loop?
My question is, how would I go about making a function that serves the same purpose of the for loop, without using any loop method.
function fl (initial, condition, iterator, code){
i = initial;
...
- 254
2
votes
4
answers
1k
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Should I always use iterators when working with strings?
Here is the known old way to iterate over the string:
for (int i = 0; i < str.length(); i++) {
char c = str[i];
}
However recently I have also seen in multiple places the usage of ...
- 131
1
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0
answers
42
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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
1
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1
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226
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How much an iterator should do
I am working on creating iterators, for strings, lists, trees, graphs, and potentially other things.
First a side note.
I have a string data type in my engine. The string is implemented as a bunch ...
- 2,661
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304
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Is there any consequences to write for(float i=0, myFloatVar=0; i < n; i++)?
For example, sometimes I need a float variable to be used inside a for loop, e.g.:
float sum=0;
for(int i = 0; i < students.length; i++) {
sum += Math.random();
students[i].result = sum;
}
...
- 5,722
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1
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What happens when loops are compiled or interpreted?
I have came across a concept in recursion which says that when loops are compiled or interpreted then they get converted to recursive functions. If it is true how it takes place ?
0
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2
answers
77
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Main Loops and listeners in live coding systems
My question is about the construction of main loops running in the background listening to commands and signals and how are they constructed to be efficient. For instance in live music synthesis ...
user230703
4
votes
5
answers
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views
Is copy and paste the head of for-loop (e.g.:for(let i=0;i<something.length;i++)) violating DRY principle?
For example, in my project, I often found some head of for-loop appears many times, eg:
for(let i=0;i<SharedData.students.length;i++){
SharedData.students[i].something=.....
}
if(isReset){
...
- 5,722
-1
votes
1
answer
420
views
How to read user input and at the same time execute periodic commands
How would I go about prompting user-input, while at the same time running timers, to periodically execute automatic functions.
Pseudo-code to illustrate:
while true
{
if input() OR timer(10)
...
2
votes
2
answers
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Can nested loop have linear time complexity
I was going through the traditional quick sort algorithm. I had a look on the partition algorithm in a couple of places and the implementation difference was very subtle. Here are the 2 approaches:
...
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Alternatives to Long Loops [closed]
I am part of a software team that is writing a console application (no UI) in C#. My part in the team is to write code to call RESTful APIs from a third party site, process the returned data and save ...
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2
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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 ...
- 5,722
3
votes
2
answers
126
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&...
- 5,722
17
votes
6
answers
8k
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Foreach-loop with break/return vs. while-loop with explicit invariant and post-condition
This is the most popular way (it seems to me) of checking if a value is in an array:
for (int x : array)
{
if (x == value)
return true;
}
return false;
However, in a book I’ve ...
- 289
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3
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410
views
Start and exit actions in while loops
Sometimes I find it useful to have loops that do an action at the beginning and/or the end of a while loop.
The best way I can think of for representing this in C++ would be:
if(condition) {
// ...
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answers
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Best practice to "continue" from inside a nested loop?
Here is a simplified sample. Basically, it does checks on a string from a string list. If the check passes, it will remove that string (filterStringOut(i);), and it is no longer ...
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Inside a for-loop, should I move the break condition into the condition field if possible? [closed]
Sometimes I need for loops which needs a break like this:
for(int i=0;i<array.length;i++){
//some other code
if(condition){
break;
}
}
I feel uncomfortable with writing
if(...
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2
answers
775
views
How do i create a logic for dynamic product list page like below using php and bootstrap?
The big image is catalog or ad blocks that comes from catalog table. And small images are the actual products block that comes from product table.
There may be more products and more catalog. ...
- 7
3
votes
2
answers
547
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While and do-while loop in the white box method of loop testing
I'm trying to understand how this method works and everywhere I check it I find there's something faulty or maybe it's that I'm not understanding something from the method.
Here there's an ...
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231
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Term for refactoring looping logic for an event loop
Constrained by a main loop outside of my control (eg: UI event loop, game loop, etc...), I have a slow (relative to the main loop's expectations) algorithm involving a loop. Thus, I have to ...
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2
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2k
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How to return boolean result from comparison loops to maintain better readability?
Let's consider I have an std::string instance filled with textual data and an std::set<std::string> instance with keywords. I would like to know whether the text stored inside the std::string ...
- 247
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Does i in for loops means iteration or index? [duplicate]
Does i in for loops means iteration or index?
How could I know the original meaning? Some programmers say it's iteration, some say it's index.
It seems to me more of an index we start from --- we go ...
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1
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What is the benefits of a foreach-loop vs a body-less for-loop
In C# you can use a for-loop without declaring the body, what is the benefit of using this in production-code versus using a foreach loop?
Example
My Examples below use reflection to get the ...
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How to apply SRP in a loop where two things need to be done?
Is there a way to apply the Single Responsibility Principle to a function where two things need to occur in a loop in order to not need to iterate twice?
For example, suppose I have a function like ...
- 242
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votes
7
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9k
views
While loop without evaluating data twice
I often come across the following pattern.
while(GetValue(i) != null)
{
DoSomethingWith(GetValue(i++));
}
Here GetValue is executed twice. It would be much nicer to use a pattern where we can ...
- 654
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votes
2
answers
323
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Permutations for time in JSON
Let's say that I have a JSON file like at example below.
How would I go about finding all possible values of item combination time sums that exist between let's say 00:03:04 to 00:25:55 without ...
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votes
2
answers
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What exactly happens when a thread awaits a task inside a while loop?
After dealing with C#'s async/await pattern for a while now, I suddenly came to realization that I don't really know how to explain what happens in the following code:
async void MyThread()
{
...
- 309
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Automatic Realtime Cycle Detection of function calls
I am running into a wall mentally when trying to think of a way to solve this problem. At my work we process customer data through some complex reasoning logic. Sometimes this logic will cause ...
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2
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Efficiency considerations: nested loop vs recursion
I would consider myself an intermediate Python programmer. One of my recent challenges was creating a list of all possible solutions to a given
Countdown problem.
Without getting into too much detail,...
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1
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how to reach all nodes in a Tree Structure where end of the tree is unknown
There is a XML link, which provides the children of any parentID given.
http://www.browsenodes.com/xml.php?action=BrowseNodeInfo&node=1036592
Then you can run the URL again with a children ID ...
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9
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Clear way to skip the first element in an index based for loop
I have a for loop where I must skip the first element in a zero-based array.
Which of these shows my intentions more clearly?
for($i=1 ; $i < count(array) ; $i++){
array[$i];
}
or
for($i=0+...
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3
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396
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Is loop unrolling one of the examples of "targeted" compilation and faster instruction set?
I'm taking the Computer Architecture course in my undergraduate study.
I see that in loop unrolling, one of the constraints is the number of available registers.
Since the number of registers ...
user236354
2
votes
2
answers
1k
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How to update a player's money count every second
I'm in the process of analysis for a browser-based game I'm making, and I have question about programming the economy system. I'll use a simplified system to ask my question.
Each user as GameState ...
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