What are good rules of thumb to use when deciding between a
NameValueCollec tion, an ArrayList, or a Hashtable ?
2  3025 
"John Grandy" <johnagrandy-at-yahoo-dot-com> wrote in message
news:Ou******** ******@TK2MSFTN GP15.phx.gbl... What are good rules of thumb to use when deciding between a
NameValueCollec tion, an ArrayList, or a Hashtable ?
Well, they are different beasts. ArrayList is a straight list with no
association with a key, whereas the other two do associate with a key. Use
it when you just need a list, not a dictionary(a collction where you can
look up a key to find a value).
NameValueCollec tion only works with strings, so its pretty much limited to
strings. Hashtable will work with any object type and is my preference for a
dictionary.
I generally go by the properties of the data structures:
ArrayList: maintains insertion order, no keyed lookup
Hashtable: keyed lookup, no defined order
SortedList: keyed lookup, maintains sorted order
I've also listed them in order of frequency of use: I use ArrayList far
more than Hashtable (because I don't often want keyed lookup), and
SortedList even less frequently (because rarely do I need both keyed
lookup and sorted order, and can't just do Hashtable -> Array and
sort).
Generally, Hashtables and SortedLists point to specialized higher-level
data structures, so I tend to wrap classes around them that offer more
specific services.
ArrayLists get used all over the place in code, casually.
This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
by: Matthias Kwiedor |
last post by:
Hi@all!
I have a app (c#) where i load up a external dll (managed code from c#)
with a small arraylist and hashtable in two routines (about 40000 objects
in each arraylist and hashtable).
If i load the dll everything is fine and when i load then the objects into
an Hashtable or Arraylist of the main program it freezes 5MB each which i
don't get free. The weird think is, when i reload the Tables a second time
on a new local variable...
|
by: Dan V. |
last post by:
I would like to create a 2D string list (2D ArrayList ???). I would like to
pass in a table or query as a parameter and have both columns transform into
a 2D ArrayList. When I sort the one 'column' in the ArrayList, the other is
automatically sorted and so I can use IndexOf without fear. This is because
I will be going through 20,000 some odd records and don't want to use a
Lookup type of table/query; I figure an ArrayList.IndexOf method...
|
by: davidw |
last post by:
I always use NameValueCollection. But I read an article says the only
differece between Hashtable and NameValueCollection is that
NameValueCollection could accept more than one value with same key? I am not
quite understand this. And I think NameValueCollection's Set is a nice
method. If I use HashTable, how can I update a item in it? Do I have to
check if it exists, and remove and add it again?
Thanks.
|
by: Matthias Kwiedor |
last post by:
Hi!
What i want to do, is to put an ArrayList into a Hashtable. So i can access
the ArrayList fast over the key-indexing of the Hashtable.
What i did is to put the ArrayList into the Hashtable
hash = arraylist
|
by: Netmonster |
last post by:
Hello,
Does any one have an example of how to create an ArrayList of objects?
i.e. ArrayList of ArrayLists or an ArrayList of Hashtables?
Thanks in advance
KC
| | |
by: paradox |
last post by:
Basically I have an ArrayList of strings; I need a fast way of
searching through and comparing the elements of the ArrayList and the
return an ArrayList of items that have 3 Duplicates.
For example, if the ArrayList has the following elements:
elems = "blue"
elems = "red"
elems = "blue"
elems = "green"
|
by: Fred |
last post by:
I'm trying to build a hashtable and a arraylist as object value
I'm not able to retrieve stored object from the hashtable.
Hashtable mp = new Hashtable(); // THE HASHTABLE
ArrayList atemp = new ArrayList(); // THE ARRAY
StreamWriter sw = new StreamWriter(@"C:\temp\fred.html");
|
by: chrisben |
last post by:
Hi,
Here is the scenario. I have a list of IDs and there are multiple threads
trying to add/remove/read from this list. I can do in C#
1. create Hashtable hList = Hashtable.Synchronized(new Hashtable());
2. create ArrayList aList = ArrayList.Synchronized(new ArrayList());
3. create a string sList = "";
For 1 and 2, since the list is synced, many threads can directly
|
by: Kamran Shafi |
last post by:
Hi,
I am creating an arraylist (say masterArrayList) of hashtables, where
each hashtable (say table) is of the format key=string, value =
arraylist of strings (say existing_strings). In a foreach loop I
retreive the corresponding hashtable from the masterArrayList and add
new strings to existing_strings after comparing the hashtable keys.
The problem is that when I add a new value to an existing_strings
arraylist it also add the new...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
| | |
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| | |
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| | |
