Questions tagged [iteration]
Iterations are the successive repetitions in loops such as for, foreach or while. Questions with this tag are often concerned about how to best handle a collection of data.
iteration
10,911
questions
43
votes
5
answers
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Converting a list of tuples into a dict
I have a list of tuples like this:
[
('a', 1),
('a', 2),
('a', 3),
('b', 1),
('b', 2),
('c', 1),
]
I want to iterate through this keying by the first item, so, for example, I could print something ...
- 35k
6
votes
7
answers
12k
views
iterative version of recursive algorithm to make a binary tree
Given this algorithm, I would like to know if there exists an iterative version. Also, I want to know if the iterative version can be faster.
This some kind of pseudo-python...
the algorithm returns ...
- 146k
55
votes
3
answers
16k
views
Why is it bad to use an iteration variable in a lambda expression
I was just writing some quick code and noticed this complier error
Using the iteration variable in a lambda expression may have unexpected results.
Instead, create a local variable within the ...
- 55.3k
1301
votes
31
answers
524k
views
Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop
We all know you can't do the following because of ConcurrentModificationException:
for (Object i : l) {
if (condition(i)) {
l.remove(i);
}
}
But this apparently works sometimes, but ...
- 227k
485
votes
17
answers
707k
views
What is the easiest/best/most correct way to iterate through the characters of a string in Java?
Some ways to iterate through the characters of a string in Java are:
Using StringTokenizer?
Converting the String to a char[] and iterating over that.
What is the easiest/best/most correct way to ...
- 64.8k
13
votes
13
answers
6k
views
Is Iterator initialization inside for loop considered bad style, and why?
Typically you will find STL code like this:
for (SomeClass::SomeContainer::iterator Iter = m_SomeMemberContainerVar.begin(); Iter != m_SomeMemberContainerVar.end(); ++Iter)
{
}
But we actually have ...
- 8,055
0
votes
6
answers
17k
views
.NET Fastest way to iterate through rows in a datatable?
Which is generally fastest when reading/comparing row info from a DataTable?
'assume dt as datatable'
'method 1'
dim i as int32
for i = 0 to dt.rows.count - 1
....
next
'method 2'
dim row as ...
- 4,285
453
votes
21
answers
201k
views
Way to go from recursion to iteration
I've used recursion quite a lot during my many years of programming to solve simple problems, but I'm fully aware that sometimes you need iteration due to memory/speed problems.
So, sometime in the ...
- 9,649
3
votes
6
answers
2k
views
Team size and project iteration length [closed]
Do you think that project iteration length is related to project team size? If so, how? What other key factors do you use to recognize correct iteration length for different projects?
- 18.6k
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vote
4
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Is it correct to use the backtick / comma idiom inside a (loop ...)?
I have some code which collects points (consed integers) from a loop which looks something like this:
(loop
for x from 1 to 100
for y from 100 downto 1
collect `(,x . ,y))
My ...
- 10.3k
13
votes
4
answers
3k
views
Is there a zip-like method in .Net?
In Python there is a really neat function called zip which can be used to iterate through two lists at the same time:
list1 = [1, 2, 3]
list2 = ["a", "b", "c"]
for v1, v2 in zip(list1, list2):
...
- 4,225
5
votes
4
answers
5k
views
How do I iterate a .Net IList collection in the reverse order?
I have an IList that contains items ( parent first ), they need to be added to a Diagram Document in the reverse order so that the parent is added last, drawn on top so that it is the first thing to ...
- 136k
17
votes
14
answers
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In C# .NET 2.0, what's an easy way to do a foreach in reverse?
Lets say I have a Dictionary object:
Dictionary myDictionary<int, SomeObject> = new Dictionary<string, SomeObject>();
Now I want to iterate through the dictionary in reverse order. I can'...
- 9,546
34
votes
9
answers
14k
views
Iterators in C++ (stl) vs Java, is there a conceptual difference?
I'm returning to c++ after being away for a bit and trying to dust off the old melon.
In Java Iterator is an interface to a container having methods: hasNext(), next() and remove(). The presence of ...
- 54.1k
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votes
46
answers
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How do I efficiently iterate over each entry in a Java Map?
If I have an object implementing the Map interface in Java and I wish to iterate over every pair contained within it, what is the most efficient way of going through the map?
Will the ordering of ...
- 38.9k