How to modify the size of an array

[Brett Hewitson]

Hello,

In Visual Basic you can redim an array to increase or decrease it's size. I
am not sure how to do this in c#.

At the moment all I can think of is the following:

1. Create a new array of the new size
2. Copy the old array into the new array
3. Null the old array.

Is there a better way to do this?

Brett

 

[Jon Skeet [C# MVP]]

In Visual Basic you can redim an array to increase or decrease it's size. I
am not sure how to do this in c#.

At the moment all I can think of is the following:

1. Create a new array of the new size
2. Copy the old array into the new array
3. Null the old array.

Is there a better way to do this?

Yes - take out step three as it's unnecessary. Just do something like:

string[] tmp = new string[newLength];
myArray.CopyTo(tmp, 0);

That's all you need.

That's what VB.NET is doing behind the scenes anyway, by the way - all
arrays in .NET are fixed size.

 

[Brett Hewitson]

Jon,

Thanks for the help and also the information. I am glad that I had the
right idea.

Brett

In Visual Basic you can redim an array to increase or decrease it's size. I
am not sure how to do this in c#.

At the moment all I can think of is the following:

1. Create a new array of the new size
2. Copy the old array into the new array
3. Null the old array.

Is there a better way to do this?

Yes - take out step three as it's unnecessary. Just do something like:

string[] tmp = new string[newLength];
myArray.CopyTo(tmp, 0);

That's all you need.

That's what VB.NET is doing behind the scenes anyway, by the way - all
arrays in .NET are fixed size.

 

[Peter Rilling]

Although, if you find that you need to continually adjust the size of an
array, you might consider using an ArrayList.

Jon,

Thanks for the help and also the information. I am glad that I had the
right idea.

Brett

In Visual Basic you can redim an array to increase or decrease it's size. I
am not sure how to do this in c#.

At the moment all I can think of is the following:

1. Create a new array of the new size
2. Copy the old array into the new array
3. Null the old array.

Is there a better way to do this?

Yes - take out step three as it's unnecessary. Just do something like:

string[] tmp = new string[newLength];
myArray.CopyTo(tmp, 0);

That's all you need.

That's what VB.NET is doing behind the scenes anyway, by the way - all
arrays in .NET are fixed size.

 

[Michael Culley]

Make sure you don't do this for every element as it will be slow. The other
alternative is to use an arraylist.

Jon,

Thanks for the help and also the information. I am glad that I had the
right idea.

Brett

In Visual Basic you can redim an array to increase or decrease it's size. I
am not sure how to do this in c#.

At the moment all I can think of is the following:

1. Create a new array of the new size
2. Copy the old array into the new array
3. Null the old array.

Is there a better way to do this?

Yes - take out step three as it's unnecessary. Just do something like:

string[] tmp = new string[newLength];
myArray.CopyTo(tmp, 0);

That's all you need.

That's what VB.NET is doing behind the scenes anyway, by the way - all
arrays in .NET are fixed size.