Creating an empty class or struct array

[AnatolParticipant]

Hi Monkeycoders,

It’s still early days for me in Monkey 2, so this is a newbie question. I’m trying to create an initially empty array of custom classes or structs, but I only managed to create the array with Length 1, not empty. Is there any better way to create that array than this (simplified code)?

Monkey

Class Control Field Name:String Field Trigger:Bool() Field Callback:Void() End Class ControlManager Field Controls := New Control[]( New Control() ) ' how can I initialise this as an empty array? Method New () Print( "Initial array length: " + Controls.Length ) ' is already Length 1 Controls = Controls.Resize( Controls.Length + 1 ) Print( "Length after resize: " Controls.Length ) ' Length 2' Controls[ Controls.Length - 1 ] = control End End

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Class Control   Field Name:String   Field Trigger:Bool()   Field Callback:Void() End   Class ControlManager   Field Controls := New Control[]( New Control() ) ' how can I initialise this as an empty array?      Method New ()     Print( "Initial array length: " + Controls.Length ) ' is already Length 1     Controls = Controls.Resize( Controls.Length + 1 )     Print( "Length after resize: " Controls.Length ) ' Length 2'     Controls[ Controls.Length - 1 ] = control   End End

I also have a related “best practice” question, but I’ll put that into a different thread.

[JesseParticipant]

to initialize an empty array you can do it like this:

Field controls := new Control[20] ' creates an array of 20 controls.

they will still be null and will need to be added to the array.

Monkey

[crayon-5cb9b9456676a217870156 inline="true" ]For Local I:int = 0 Until 20 controls[I] = New Control() Next

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[crayon-5cb9b9456676a217870156 inline="true" ]For Local I:int = 0 Until 20      controls[I] = New Control() Next

[/crayon]

you can also add them in line like this:

Field controls := new Control[](New Control(),New Control(), New Control() ]
`

[AnatolParticipant]

Oh! Thanks Jesse. I could’ve sworn that I tried this, but apparently not. And yes, that works well, even with length 0.

[TomToadParticipant]

To create a zero length array, use ArrayName:Type[]. Then you can use Resize or New to add to the array

Monkey

Namespace myapp #Import "<std>" Using std.. Class Control Field Name:String Field Trigger:Bool() Field Callback:Void() End Function Main() Local Controls:Control[] '0 length controls For Local i:Int = 0 To 3 Print ("Length before adding control = "+Controls.Length) Controls = Controls.Resize(i+1) Print ("Length after adding control = "+Controls.Length) Controls[i] = New Control 'add the instance to the array Controls[i].Name = "Control #"+i Next For Local control := Eachin Controls Print control.Name Next End

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Namespace myapp   #Import "<std>"   Using std..   Class Control   Field Name:String   Field Trigger:Bool()   Field Callback:Void() End       Function Main() Local Controls:Control[] '0 length controls For Local i:Int = 0 To 3 Print ("Length before adding control = "+Controls.Length) Controls = Controls.Resize(i+1) Print ("Length after adding control = "+Controls.Length) Controls[i] = New Control 'add the instance to the array Controls[i].Name = "Control #"+i Next For Local control := Eachin Controls Print control.Name Next End

[nerobotParticipant]

Local Controls:Control[] ‘0 length controls

really! why it’s not a null object?! magic.

[TomToadParticipant]

Arrays are a bit weird. A zero length array acts like a Null object, but at the same time has a Length property which it shouldn’t if the array is truly Null.

Monkey

Local IntArray:Int[] If IntArray = Null 'The array is Null Print "Array is Null" Else Print "Array is not Null" End If Print "Array length = "+IntArray.Length 'However, it still has a Length property

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Local IntArray:Int[] If IntArray = Null 'The array is Null Print "Array is Null" Else Print "Array is not Null" End If Print "Array length = "+IntArray.Length 'However, it still has a Length property

[Author]

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