[2 days left] What’s wrong with your cloud strategy? Learn why multicloud solutions matter with Nimble Storage.Register Now

x
?
Solved

vb.net delete random from ArrayList

Posted on 2013-10-31
5
Medium Priority
?
520 Views
Last Modified: 2013-10-31
Hello,
I have an ArrayList called "lastnames" with 20 items.
I would like to know whats the easiest way to remove random items from it leaving it with only 5 records.. how can I do this?
0
Comment
Question by:XK8ER
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 2

Expert Comment

by:BakuRetsu_X
ID: 39615352
Create a random number generator object up to the size of your matrix.
Once you grab a number, take that as your array index to remove from the array.
Are you looking for code example?

Search vb.net random number generator on google.
Then search remove from array list vb.net.
0
 
LVL 1

Author Comment

by:XK8ER
ID: 39615359
yeah I tried that but for example I do

myAL.RemoveAt(5)
myAL.RemoveAt(8)
myAL.RemoveAt(12)

at this point i have only 17 items in the arraylist so when I do

myAL.RemoveAt(19)

it crashes
0
 
LVL 75

Assisted Solution

by:käµfm³d 👽
käµfm³d   👽 earned 1000 total points
ID: 39615682
Make sure the next random number you generate is never larger than the maximum index of your collection.

e.g.

Dim rand As New Random()
Dim myAL As New ArrayList() = SomeInitialization()
Dim toRemove As Integer = rand.Next(0, myAL.Count)

myAL.RemoveAt(toRemove)

Open in new window

0
 
LVL 86

Accepted Solution

by:
Mike Tomlinson earned 1000 total points
ID: 39615786
Another quick example:
        Dim R As New Random
        While lastnames.Count > 5
            lastnames.RemoveAt(R.Next(lastnames.Count))
        End While

Open in new window

0
 
LVL 2

Expert Comment

by:BakuRetsu_X
ID: 39615795
Remember.  The array is constantly shrinking also. So each time you want the random number to be within the length of it.
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
Performance in games development is paramount: every microsecond counts to be able to do everything in less than 33ms (aiming at 16ms). C# foreach statement is one of the worst performance killers, and here I explain why.
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…
How to fix incompatible JVM issue while installing Eclipse While installing Eclipse in windows, got one error like above and unable to proceed with the installation. This video describes how to successfully install Eclipse. How to solve incompa…

656 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question