| Description |
The Slice function creates a sub-array from the first Count elements of an array, SourceArray.
It can ONLY be used as an argument for an 'Open array' parameter of a procedure or function.
An 'Open array' parameter is one that has an unknown number of array elements at compile time.
This allows for a routine to work with variable sized arrays.
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| Related commands |
| Array |
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A data type holding indexable collections of data |
| Copy |
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Create a copy of part of a string or an array |
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| Example code : Passing an array slice to a procedure |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
// The System unit does not need to be defined
SysUtils,
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
procedure ShowSlice(SubArray : array of Integer);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
i : Integer;
Source : array[0..4] of Integer;
begin
// Create the source array with 0..4 values for elements 0..4
for i := 0 to 4 do
Source[i] := i;
// Use the Slice command to pass just the first 3 elements of Source as
// an open array to the ShowSlice procedure below.
ShowSlice(Slice(Source, 3));
end;
// Show an array of unknown size - it is passed as an 'Open' array
procedure TForm1.ShowSlice(SubArray : array of Integer);
var
i : Integer;
begin
// Show every element of this array
for i := 0 to Length(SubArray)-1 do
ShowMessage('SubArray['+IntToStr(i)+'] : '+ IntToStr(SubArray[i]));
end;
end.
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| Hide full unit code |
SubArray[0] : 0
SubArray[1] : 1
SubArray[2] : 2
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