This is a new site that's currently running on alpha code. There are going to be bugs. If you discover any, please report them on the site's issues page (GitHub account required). Thanks.
Warning: Many URLs are going to change. Refer to the README file to discover which library project's documentation has been completed.
Project: Array Utilities Unit
Unit: DelphiDabbler.Lib.ArrayUtils
Record: TArrayUtils
Applies to: ~>0.1
class function Equal<T>(const ALeft, ARight: array of T;
const AEqualityComparer: TEqualityComparison<T>): Boolean;
overload; static;
class function Equal<T>(const ALeft, ARight: array of T;
const AEqualityComparer: IEqualityComparer<T>): Boolean;
overload; static;
class function Equal<T>(const ALeft, ARight: array of T): Boolean;
overload; static;
Checks if two arrays, both with elements of of the same type, have the same contents, in the same order.
Parameters:
ALeft - The first array to be compared.
ARight - The second array to be compared.
AEqualityComparer - An optional function or object that is used to test the equality of two values. Used to check equality of array elements.
If AEqualityComparer is provided it must be one of:
If the parameter is omitted then the default equality comparer defined by Delphi’s TEqualityComparer<T>.Default method is used.
Returns:
True if ALeft and ARight are the same or False if not.Two non-empty arrays are considered equal if, and only if, both arrays have the same length and the elements at the same index in each array are equal.
Two empty arrays are considered equal.
Using a comparer function:
procedure Equal_Eg1;
var
A, B, C, D, E1, E2: TArray<Integer>;
EqComparerFn: TEqualityComparison<Integer>;
begin
A := TArray<Integer>.Create(1, 2, 3);
B := TArray<Integer>.Create(1, 2, 3);
C := TArray<Integer>.Create(1, 2);
D := TArray<Integer>.Create(1, 5, 7);
E1 := TArray<Integer>.Create(); // empty
E2 := TArray<Integer>.Create(); // empty
EqComparerFn := function(const Left, Right: Integer): Boolean
begin
Result := Left = Right;
end;
Assert(TArrayUtils.Equal<Integer>(A, B, EqComparerFn) = True);
Assert(TArrayUtils.Equal<Integer>(A, C, EqComparerFn) = False);
Assert(TArrayUtils.Equal<Integer>(A, D, EqComparerFn) = False);
Assert(TArrayUtils.Equal<Integer>(A, E1, EqComparerFn) = False);
Assert(TArrayUtils.Equal<Integer>(E1, E2, EqComparerFn) = True);
end;
Using a comparer object:
procedure Equal_Eg2;
var
A, B, C, D, E1, E2: TArray<string>;
EqComparerObj: IEqualityComparer<string>;
begin
A := TArray<string>.Create('a', 'b', 'c');
B := TArray<string>.Create('a', 'b', 'c');
C := TArray<string>.Create('a', 'b');
D := TArray<string>.Create('a', 'd', 'f');
E1 := TArray<string>.Create(); // empty
E2 := TArray<string>.Create(); // empty
EqComparerObj := TDelegatedEqualityComparer<string>.Create(
SameStr,
function (const Value: string): Integer
begin
// This is only safe because the hash function isn't called by Equal
Result := 0;
end
);
Assert(TArrayUtils.Equal<string>(A, B, EqComparerObj) = True);
Assert(TArrayUtils.Equal<string>(A, C, EqComparerObj) = False);
Assert(TArrayUtils.Equal<string>(A, D, EqComparerObj) = False);
Assert(TArrayUtils.Equal<string>(A, E1, EqComparerObj) = False);
Assert(TArrayUtils.Equal<string>(E1, E2, EqComparerObj) = True);
end;