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Project: Array Utilities Unit
Unit: DelphiDabbler.Lib.ArrayUtils
Record: TArrayUtils
Applies to: ~>0.1
class function CopySorted<T>(const A: array of T;
const AComparer: TComparison<T>): TArray<T>;
overload; static;
class function CopySorted<T>(const A: array of T;
const AComparer: IComparer<T>): TArray<T>;
overload; static;
class function CopySorted<T>(const A: array of T): TArray<T>;
overload; static;
Returns a sorted copy of an array.
The copy is a shallow copy, so any references within the resulting array are the same as those in the initial array.
Parameters:
A - The array to be sorted.
AComparer - An optional function or object that can be used to compare two values. Determines the sort order of the array.
If AComparer is provided it must be one of:
If this parameter is omitted then the default comparer defined by the TComparer<T>.Default method from the Delphi’s System.Generics.Defaults unit is used.
Returns:
If a deep copy of the sorted array is required then pass the return value of CopySorted<T> to the deep copying overload of Copy<T> along with a suitable TCloner<T> implementation.
The first example uses a comparer function to reverse sort an array of integers.
procedure CopySorted_Eg1;
var
A, Got, Expected: TArray<Integer>;
ReverseComparerFn: TComparison<Integer>;
begin
A := TArray<Integer>.Create(1, 2, 3, 4, 2, 3, 2);
ReverseComparerFn := function(const Left, Right: Integer): Integer
begin
// reverse sort
Result := Right - Left;
end;
Got := TArrayUtils.CopySorted<Integer>(A, ReverseComparerFn);
Expected := TArray<Integer>.Create(4, 3, 3, 2, 2, 2, 1);
Assert(TArrayUtils.Equal<Integer>(Expected, Got));
end;
The second example uses a comparer object to sort an array of strings.
procedure CopySorted_Eg2;
var
A, Got, Expected: TArray<string>;
ComparerObj: IComparer<string>;
begin
ComparerObj := TDelegatedComparer<string>.Create(
function (const Left, Right: string): Integer
begin
Result := CompareStr(Left, Right);
end
);
A := TArray<string>.Create(
'dave', 'dee', 'dozy', 'beaky', 'mick', 'and', 'titch'
);
Got := TArrayUtils.CopySorted<string>(A, ComparerObj);
Expected := TArray<string>.Create(
'and', 'beaky', 'dave', 'dee', 'dozy', 'mick', 'titch'
);
Assert(TArrayUtils.Equal<string>(Expected, Got, SameStr));
end;