Questions tagged [iterator]

An iterator is an object-oriented programming pattern which for the most part functions similarly to a pointer to an object inside a collection with the added ability to traverse through the collection in a defined manner, agnostic of the actual implementation or even object addresses in physical memory. Iterators may be further limited in particular traversal directions.

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5
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7k views

Iterator for a list of objects

Given a list of objects, return an iterator for such a list. Looking for code-review, optimizations and best practices. Verifying complexity to be O(n) where n is sum of all objects, including ...
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Linked list with iterators

This is my second linked list implementation for review. I rewritten pretty much all of this and have added iterators, sentinels and The Rule of Five. Please let me know what's wrong with it; I am ...
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1answer
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Container which iterates a range or a list

I have made some composited container Range which accepts either a min/max range as a std::pair or a set of integers as a ...
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2answers
853 views

Recursive flatten with lazy evaluation iterator

I'm trying to rewrite this: ...
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5answers
824 views

A deduplicating iterator

Implement an iterator (generic) which skips an element if it is equal to the previous element. e.g: AAABBCCCCD, produces ABCD. Please suggest improvements. ...
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4answers
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Simple Example of an Iterable and an Iterator in Java

I was a TA for a first-year Java programming course this year. As a very simple example of iterables/iterators, I wrote the following code for the students. I am curious if any styling or other ...
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Using a Pythonesque range() generator function with the Java foreach loop

Now that we have the nice new foreach loop in Java, the old-style loop looks ugly be comparison. I like the way Python has a ...
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2answers
14k views

Iterator for binary tree - pre, in, and post order iterators

Implemented iterator for a binary tree and "pre" "in" and "post" order flavors. I'm looking for code review, best practices, optimizations etc. ...
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2answers
888 views

Iterator class using a square list

I am trying to implement squarelist by using iteration that points to the head element. I've create this iterator class to make my iterator id directional. I just want to see if I implemented it ...
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2answers
10k views

Creating linked list data with iterator pattern

I've created a linked list to use it in SquareList. I've started to create a linked list based on just that. I want my class to follow the iterator pattern. How can it be improve to use vector ...
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1answer
233 views

Serializing tabular data in ruby — is map, flatten, hash the correct approach?

I wanted a hash which lets me reference Japanese syllables by their romanized names. In hindsight I could have searched for an existing one column table, but I wanted to improve my ruby by writing a ...
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0answers
554 views

REST Response: Checking for Success and Error

I thought this was pretty slick - maybe not, I just wanted to share and maybe get some feedback: As part of a REST client class: Accepts the JSON response from REST or REST-like service, searches ...
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1answer
2k views

Iterator adaptor for iterators returning tuple-like values

Today, I will require your help to improve an iterator adapter. The goal of the adapter (I called it get_iterator) is to adapt ...
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1answer
16k views

Nested select Linq

Is there a simpler and optimized way to calculate listAdminCorePriveleges and privileges ? ...
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1answer
39k views

Iterator Implementation

I had to write my own iterator implementation for my structure which has ArrayList<Vector> field. An iterator is supposed to iterate over mentioned ...
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3answers
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Check IEnumerable Count

Let's say I have a collection of expensive-to-generate objects stored in an IEnumerable: ...
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1answer
4k views

Filtering a long list of files through a set of ignore patterns using iterators

I have a backup job that walks across a huge directory with potentially millions of files. Python's os.walk() works just fine. Now, I have implemented a feature to ignore files based in a black list ...
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3answers
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Flatten iterator for nested list

Given a list which can can contain elements as well as lists, write an iterator to flatten a nested list. Please make this code better and suggest any improvements. ...
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2answers
241 views

Remove item from a list, which (of the 2) methods is better?

I have a List, and I have to delete one item from the list when I find it. I am using the code below to do that: ...
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3answers
18k views

“Zip-like” functionality with C++11's range-based for-loop

My goal was to get the following code to work: ...
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1answer
118 views

copy_if_max() algorithm

I need a copy_if_max() function, i.e. copy all the elements in an input range that are equal to the max in that range. The most obvious implementation does two ...
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1answer
1k views

Refactor IQueryable and IEnumerable that share the same condition

I have extension methods to encapsulate query conditions, however I have to separate IQueryable and IEnumerable. Is there any ...
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3answers
1k views

Is this a correct recursive Scala iterator creation?

I am diving into Scala (using 2.10) headfirst and am trying out a simple task of taking bulk data and then doing something with that stream. The first part is generating that stream. I have seem to be ...
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1answer
3k views

Creating custom random access iterator in C++ 2011

I would like an opinion on my code. I need a random access iterator for my custom container. If I read the C++ 2011 standard, specially chapter 24, I understood that an implementation could be the ...
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1answer
219 views

How to remove goto statement from iterator

I'm implementing a simple iterator in C# over an xml document, in order to process an xml document in as much a streaming manner as possible. For this reason, I'm using an XmlReader variable in a <...
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1answer
656 views

Python reversed in C++11

I was playing with some of the wonderful new C++11 features and tried to reimplement a function reversed that would behave just like the one in Python to allow ...
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3answers
6k views

Most efficient way to iterate through arrays/can I use .times method in place of while method?

I created a quick program to test the precision of randomness generated by the .rand method. The primary question is whether I can use the ...
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1answer
15k views

How to make an iteration in a for-loop faster?

I have a list with contentlets and want all languages from every contentlet (I get these with the method ...
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1answer
1k views

Setting output width with ostream_iterator

I'd like to display a vector (implemented in my custom Vector class) and have the output width of the elements be configurable. I've done this by creating a simple ...
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1answer
1k views

Iterator and Generator versions of Python's range()

I have created iterator and generator versions of Python's range(): Generator version ...
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1answer
740 views

Polymorphic STL foreach without passing the container type

I was trying to figure out how to make a breakable foreach macro for STL containers and I came up with this method that uses templates to recognize the container type automatically. Are there any ...
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3answers
3k views

Converting base-10 numbers into base-26 letters

I'm writing something that basically takes a bunch of files and renames them into a nice format, such as pic_000.jpeg, ...
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6answers
2k views

infix_iterator code

I've previously posted this on Stack Overflow, and am considering submitting it to Boost for wider distribution, but thought perhaps it would be best to put it up here for peer review first, and see ...
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2answers
1k views

Leap year program

I'm switching to Ruby from Java and so, for exercise purposes, I wrote this verbose leap year Ruby program. The comments express my concerns about Ruby best practices. I'd be glad if some Ruby ...
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3answers
3k views

Generic cached IEnumerable<T>

I've an IEnumerable<T> source which takes time to generate each item. Once an item is generated, I want to cache it to avoid recomputing the same thing. I ...
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4answers
726 views

Iterator-like interface for extracting records from a blob

I have a blob whose format is something like: (id1,key1,value1)(id2,key2,value2).... where id is a uint32_t, and key and value are null-terminated strings. I am ...
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1answer
2k views

Tortoise and hare cycle detection algorithm using iterators in Python

Reading the article in Wikipedia about cycle detection I came across a relatively small code snipped of Floyd's cycle-finding algorithm. I'll put it here to keep everything in one place: ...
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1answer
150 views

Iterating through 128-byte records in a file

I need to read records from a flat file, where each 128 bytes constitutes a logical record. The calling module of this below reader does just the following. ...
4
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1answer
115 views

Skip_over() algorithm

I'm just curious if this is clear to the average person. ...
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2answers
442 views

Iterating over unequal unordered pairs in one collection

This code kinda hurts my feelings -- everything else in my code is done in neat one-liners, exploiting algorithms and, sometimes boost::bind, except for this piece. ...
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2answers
25k views

How can I avoid unchecked cast warning in my generic recursive Iterator?

It's somewhat odd that Java's collection framework has no iterator for recursive data structures. Since I needed something like this, I wrote my own. First off, I need recursive elements: ...
3
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4answers
4k views

Iterator pattern/iterator class

I have implemented a simple iterator. Just want to check if I have missed anything. ...
6
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1answer
3k views

Iterator over row and columns

I am writing a simple raytracer just for fun. I want to iterate over rows, and each row must be an iterator over columns. A strategy I produced is the following: ...
4
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3answers
552 views

LISP-like list class

So, here's my code: ...
2
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1answer
168 views

Can you make this Key-interable view of a List of Maps better?

I have a list of map entries, and I need an iterable that returns the keys. Of course, we could be naive and copy over into a new collection of the desired type, but that's inefficient. So let's ...
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3answers
2k views

Is ToIEnumerable<T> good practice?

I have an extension method that does this: ...
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2answers
597 views

Sudoku Grid special purpose Iterators

Please have a look at these iterators which I use for my Sudoku solver. They behave slightly different from STL iterators and don't implement all functionality that would be needed to use them in a ...