I want to fill the last three Edit's with the elements of r. Somehow the value of i is not changing. Please have a look!
procedure TForm1.Button1Click(Sender: TObject);
var
r: Array of Real;
cod,h,N,code,i: Integer;
value: Real;
begin
Val(Edit1.Text, cod, code);
Val(Edit2.Text, h, code);
Val(Edit3.Text, N, code);
Edit1.Text := Edit1.Text;
Edit2.Text := Edit2.Text;
Edit3.Text := Edit3.Text;
setlength(r, N);
i:= 0;
while i<= N do
begin
r[i] := cod/2 + h*i;
i := i + 1;
end;
Edit4.Text := formatfloat('#.0', r[0]);
Edit5.Text := formatfloat('#.0', r[1]);
Edit6.Text := formatfloat('#.0', r[2]);
end;
end.
Your code contains a lot of useless and buggy code. So I will fix it as far I can do from the given informations. I added a prefix L to all local variables
procedure TForm1.Button1Click(Sender: TObject);
var
Lr : Array[0..2] of Real;
Lcod, Lh : Integer;
LIdx : Integer;
begin
// throws an exception if Edit1.Text cannot converted to an Integer
Lcod := StrToInt( Edit1.Text );
// throws an exception if Edit2.Text cannot converted to an Integer
Lh := StrToInt( Edit2.Text );
for LIdx := 0 to 2 do
Lr[LIdx] := Lcod/2 + Lh*LIdx;
Edit4.Text := FormatFloat( '#.0', Lr[0] );
Edit5.Text := FormatFloat( '#.0', Lr[1] );
Edit6.Text := FormatFloat( '#.0', Lr[2] );
end;
Related
I am trying to animate a dropdown menu of 7 images using a for loop, using a different component to change after each iteration of the code inside the for loop. For example, the first time the loop runs: imgCourses7.Top is used, but the second time the loop runs (when I = 1) then imgCourses6.Top should be used instead.
iCoursesCount := 7;
iTotalLength := (6+41)*iCoursesCount;
imgCourses7.Top := 6;
imgCourses6.Top := 6;
imgCourses5.Top := 6;
imgCourses4.Top := 6;
imgCourses3.Top := 6;
imgCourses2.Top := 6;
imgCourses1.Top := 6;
for I := 0 to iCoursesCount -1 do
begin
while not(imgCourses7.Top = iTotalLength - 41*(I+1)) do
begin
imgCourses8.Top := imgCourses8.Top + 6;
sleep(8);
application.ProcessMessages;
if imgCourses7.Top >= iTotalLength - 41*(I+1) then
begin
imgCourses7.Top := iTotalLength - 41*(I+1);
break;
end;
end;
end;
Like #AndreasRejbrand said in a comment, you can use an array, eg:
var
Images: array[0..6] of TImage;
TargetTop: Integer;
...
...
Images[0] := imgCourses7;
Images[1] := imgCourses6;
Images[2] := imgCourses5;
Images[3] := imgCourses4;
Images[4] := imgCourses3;
Images[5] := imgCourses2;
Images[6] := imgCourses1;
iCoursesCount := Length(Images);
TargetTop := 6+(41*iCoursesCount);
for I := 0 to iCoursesCount-1 do begin
Images[I].Top := 6;
end;
for I := 0 to iCoursesCount-1 do
begin
Dec(TargetTop, 41);
while Images[I].Top <> TargetTop do
begin
Images[I].Top := Images[I].Top + 6;
Sleep(8);
Application.ProcessMessages;
if Images[I].Top >= TargetTop then
begin
Images[I].Top := TargetTop;
Break;
end;
end;
end;
That being said, you really shouldn't be using a sleeping loop that requires Application.ProcessMessages() on each iteration. You might consider using a TTimer or TThread.ForceQueue() instead. Don't block the main UI thread unnecessarily. For example:
published
procedure FormCreate(Sender: TObject);
private
Images: array[0..6] of TImage;
TargetTop: Integer;
CurrentImage: Integer;
procedure StartAnimatingMenu;
procedure StartAnimatingNextMenuItem;
procedure StepAnimateCurrentMenuItem;
...
...
procedure TMyForm.FormCreate(Sender: TObject);
begin
Images[0] := imgCourses7;
Images[1] := imgCourses6;
Images[2] := imgCourses5;
Images[3] := imgCourses4;
Images[4] := imgCourses3;
Images[5] := imgCourses2;
Images[6] := imgCourses1;
end;
procedure TMyForm.StartAnimatingMenu;
var
I: Integer;
begin
for I := Low(Images) to High(Images) do begin
Images[I].Top := 6;
end;
TargetTop := 6+(41*Length(Images));
CurrentImage := -1;
StartAnimatingNextMenuItem;
end;
procedure TMyForm.StartAnimatingNextMenuItem;
begin
Inc(CurrentImage);
if CurrentImage < Length(Images) then
begin
Dec(TargetTop, 41);
StepAnimateCurrentMenuItem;
end;
end;
procedure TMyForm.StepAnimateCurrentMenuItem;
begin
if Images[CurrentImage].Top <> TargetTop then
begin
Images[CurrentImage].Top := Images[CurrentImage].Top + 6;
TThread.ForceQueue(nil, StepAnimateCurrentMenuItem, 8);
end
else if Images[CurrentImage].Top >= TargetTop then
begin
Images[CurrentImage].Top := TargetTop;
StartAnimatingNextMenuItem;
end;
end;
I am trying to copy an OleVariant array to my own structure. I received the OleVariant from an external COM call.
The size is 1000 x 500 elements (I don't know if its the same as this Structure Definition: array of array of OleVariant).
Currently, I am trying to achieve something like:
result := Copy(Source, Amount)
But the OleVariant structure is in my way.
If I use a "classical" loop, it works, but it is slow (very slow).
aResult is currently defined as TData = array of array of string;
procedure CopyResult(aResultCount: Integer; var aResult: TData; aSource: Variant);
var
i, j: Integer;
bVariantConversion: boolean;
begin
SetLength(aResult, aResultCount, VarArrayHighBound(aSource[0], 1));
bVariantConversion := NullStrictConvert; // settings to manage how string conversion for Variant is handled.
NullStrictConvert := False;
try
for i := VarArrayLowBound(aSource, 1) to VarArrayHighBound(aSource, 1) do
begin
for j := VarArrayLowBound(aSource[i], 1) to pred(VarArrayHighBound(aSource[i], 1)) do
begin
//nearly every execution pause is somewhere in this String Conversion or Array Function.
aResult[i][j] := aSource[i][j]; //implicit conversion to string ...
end;
end;
finally
NullStrictConvert := bVariantConversion;
end;
end;
As #Remy Lebau mentioned the bounds Check for the Vararray[x][y] access is the routine my source burns its time. I am trying to eliminate this kind of acces by going directly to the OleVariantArray Elements.
Aftermath...
trying to Determine my Structure i think i found the Root.
tmyVarType := VarType(aSource); //8204 => Array(VT_ARRAY = 0x2000 = 8192) + variant(VT_VARIANT = 0x000C = 12)
tmyVarType := VarType(aSource[0]); //8204
tmyVarType := VarType(aSource[0][0]); //3 VT_I4 = 0x0003 = 3 is integer and this is correctly changin for the fields.
So i try to acess the Source without the build in functions to avoid the bounds check.
The biggest bottleneck in this code is the bounds checking performed by the [] operator on each Variant array, and potentially on your aResult array, too. Since you are already handling the bounds in each loop, there is no need to verify the bounds inside of the loops as well.
So, if performance is an issue for you, then you can use VarArrayLock() to access the underlying Variant elements in each array, using pointer arithmetic to move between them, eliminating those redundant bounds checks.
You should also reduce the redundant calls to VarArray(Low|High)Bound(aSource[i], 1) on each iteration of the outer array, since you claim the inner arrays all have the same length. So you can calculate that up front before entering the loops.
Try something like this:
type
TStrArr = array of string;
PStrArr = ^TStrArr;
TData = array of TStrArr;
procedure CopyResult(aResultCount: Integer; var aResult: TData; aSource: Variant);
var
i, j,
OuterLBound, OuterHBound, OuterCount,
InnerLBound, InnerHBound, InnerCount: Integer;
pOuterVarArr, pInnerVarArr: PVariant;
pOuterDynArr: PStrArr;
pInnerDynArr: PString;
bVariantConversion: boolean;
begin
aResult := nil;
Assert(VarIsType(aSource, varArray or varVariant));
Assert(VarArrayDimCount(aSource) = 1);
OuterLBound := VarArrayLowBound(aSource, 1);
OuterHBound := VarArrayHighBound(aSource, 1);
OuterCount := {aResultCount} OuterHBound - OuterLBound + 1;
if OuterCount < 1 then Exit;
Assert(VarIsType(aSource[0], varArray or varVariant));
Assert(VarArrayDimCount(aSource[0]) = 1);
InnerLBound := VarArrayLowBound(aSource[0], 1);
InnerHBound := VarArrayHighBound(aSource[0], 1);
InnerCount := InnerHBound - InnerLBound + 1;
SetLength(aResult, {aResultCount} OuterCount, InnerCount);
bVariantConversion := NullStrictConvert; // settings to manage how string conversion for Variant is handled.
NullStrictConvert := False;
try
pOuterDynArr := PStrArr(aResult);
pOuterVarArr := PVariant(VarArrayLock(aSource));
try
for i := OuterLBound to OuterHBound do
begin
pInnerDynArr := PString(pOuterDynArr^);
pInnerVarArr := PVariant(VarArrayLock(pOuterVarArr^));
try
//System.Variants.DynArrayFromVariant(pOuterDynArr^, pInnerVarArr^, TypeInfo(String));
for j := InnerLBound to InnerHBound do
begin
pInnerDynArr^ := pInnerVarArr^; //implicit conversion to string ...
Inc(pInnerDynArr);
Inc(pInnerVarArr);
end;
finally
VarArrayUnlock(pOuterVarArr^);
end;
Inc(pOuterDynArr);
Inc(pOuterVarArr);
end;
finally
VarArrayUnlock(aSource);
end;
finally
NullStrictConvert := bVariantConversion;
end;
end;
On the other hand, if there is ever a chance that the inner arrays have different lengths, then you can try this adjustment instead:
type
TStrArr = array of string;
PStrArr = ^TStrArr;
TData = array of TStrArr;
procedure CopyResult(aResultCount: Integer; var aResult: TData; aSource: Variant);
var
i, j,
OuterLBound, OuterHBound, OuterCount,
InnerLBound, InnerHBound, InnerCount: Integer;
pOuterVarArr, pInnerVarArr: PVariant;
pOuterDynArr: PStrArr;
pInnerDynArry: PString;
bVariantConversion: boolean;
begin
aResult := nil;
Assert(VarIsType(aSource, varArray or varVariant);
Assert(VarArrayDimCount(aSource) = 1);
OuterLBound := VarArrayLowBound(aSource, 1);
OuterHBound := VarArrayHighBound(aSource, 1);
OuterCount := {aResultCount} OuterHBound - OuterLBound + 1;
if OuterCount < 1 then Exit;
SetLength(aResult, {aResultCount} OuterCount);
bVariantConversion := NullStrictConvert; // settings to manage how string conversion for Variant is handled.
NullStrictConvert := False;
try
pOuterDynArr := PStrArr(aResult);
pOuterVarArr := PVariant(VarArrayLock(aSource));
try
for i := OuterLBound to OuterHBound do
begin
pInnerVarArr := PVariant(VarArrayLock(pOuterVarArr^));
try
//System.Variants.DynArrayFromVariant(pOuterDynArr^, pInnerVarArr^, TypeInfo(String));
Assert(VarIsType(pInnerVarArr^, varArray or varVariant);
Assert(VarArrayDimCount(pInnerVarArr^) = 1);
InnerLBound := VarArrayLowBound(pInnerVarArr^, 1);
InnerHBound := VarArrayHighBound(pInnerVarArr^, 1);
InnerCount := InnerHBound - InnerLBound + 1;
SetLength(pOuterDynArr^, InnerCount);
pInnerDynArr := PString(pOuterDynArr^);
for j := InnerLBound to InnerHBound do
begin
pInnerDynArr^ := pInnerVarArr^; //implicit conversion to string ...
Inc(pInnerDynArr);
Inc(pInnerVarArr);
end;
finally
VarArrayUnlock(pOuterVarArr^);
end;
Inc(pOuterDynArr);
Inc(pOuterVarArr);
end;
finally
VarArrayUnlock(aSource);
end;
finally
NullStrictConvert := bVariantConversion;
end;
end;
Edit: I Only tested the Source version for all Entrys the same length but it works my own partial [] free Version used ~5 Million cycles with Tstopwatch ElapsedTicks and this one only took around ~2 Millon (more like 1.6) Thanks
I have 2 arrays that I need to align lines. I prepare the 'control' array which has the info on how to align arrays and then I do it, with help of temp arrays.
See in picture the arrays and result as aligned arrays:
Here is the code that I use, as MCVE:
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls,
System.Math,
System.Generics.Defaults,
System.Generics.Collections;
type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
TSide = (sLeft, sRight, sBoth);
TData = record
DataID: integer;
DataName: string;
BlankLine: boolean;
end;
TCtrlData = record
Side: TSide;
Idx_l: integer;
Idx_r: integer;
end;
var
Form1: TForm1;
aLeft, aRight, aLeft_tmp, aRight_tmp: TArray<TData>; // main and temp arrays
aCtrl: TArray<TCtrlData>; // control array with instructions o nhow to align lines
implementation
{$R *.dfm}
procedure PrepareData;
begin
// prepare data
SetLength(aLeft, 4);
aLeft[0].DataID := 1; aLeft[0].DataName := 'One';
aLeft[1].DataID := 2; aLeft[1].DataName := 'Three';
aLeft[2].DataID := 3; aLeft[2].DataName := 'Six';
aLeft[3].DataID := 4; aLeft[3].DataName := 'Eight';
SetLength(aRight, 6);
aRight[0].DataID := 1; aRight[0].DataName := 'One';
aRight[1].DataID := 2; aRight[1].DataName := 'Two';
aRight[2].DataID := 3; aRight[2].DataName := 'Four';
aRight[3].DataID := 4; aRight[3].DataName := 'Five';
aRight[4].DataID := 5; aRight[4].DataName := 'Seven';
aRight[5].DataID := 6; aRight[5].DataName := 'Eight';
// do the magic - prepare control array
SetLength(aCtrl, 8);
aCtrl[0].Side := sBoth; aCtrl[0].Idx_L := 0; aCtrl[0].Idx_R := 0;
aCtrl[1].Side := sRight; aCtrl[1].Idx_R := 1;
aCtrl[2].Side := sLeft; aCtrl[2].Idx_L := 1;
aCtrl[3].Side := sRight; aCtrl[3].Idx_R := 2;
aCtrl[4].Side := sRight; aCtrl[4].Idx_R := 3;
aCtrl[5].Side := sLeft; aCtrl[5].Idx_L := 2;
aCtrl[6].Side := sRight; aCtrl[6].Idx_R := 4;
aCtrl[7].Side := sBoth; aCtrl[7].Idx_L := 3; aCtrl[7].Idx_R := 5;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
i, vIndex: integer;
begin
PrepareData;
{ prepare arrays based on Control array
Loop through Control array and fill temp arrays from Left or Right arrays }
SetLength(aLeft_tmp, 0);
SetLength(aRight_tmp, 0);
SetLength(aLeft_tmp, Length(aCtrl));
SetLength(aRight_tmp, Length(aCtrl));
vIndex := 0;
for i := 0 to High(aCtrl) do
begin
if aCtrl[i].Side = sBoth then // Data from Both
begin
aLeft_tmp[vIndex] := aLeft[aCtrl[i].Idx_L];
aRight_tmp[vIndex] := aRight[aCtrl[i].Idx_R];
Inc(vIndex);
end;
if aCtrl[i].Side = sLeft then // Data from Left side
begin
aLeft_tmp[vIndex] := aLeft[aCtrl[i].Idx_L];
aRight_tmp[vIndex].BlankLine := true;
Inc(vIndex);
end;
if aCtrl[i].Side = sRight then // Data from Right side
begin
aRight_tmp[vIndex] := aRight[aCtrl[i].Idx_R];
aLeft_tmp[vIndex].BlankLine := true;
Inc(vIndex);
end;
end;
// Assign aligned data to main arrays
aLeft := aLeft_tmp;
aRight := aRight_tmp;
end;
As I use the same or similar code for a lot of arrays, I'm trying to refactor and simplify it with AlignArrays function:
procedure AlignArrays(vCtrl: TArray<TCtrlData>; var vLeft, vRight: TArray<TData>);
var
i, vIndex: integer;
vLeft_tmp, vRight_tmp: TArray<TData>;
begin
SetLength(vLeft_tmp, Length(vCtrl));
SetLength(vRight_tmp, Length(vCtrl));
vIndex := 0;
{ prepare arrays based on Control array
Loop through Control array and fill temp arrays from Left or Right arrays }
for i := 0 to High(vCtrl) do
begin
if vCtrl[i].Side = sBoth then // Data from Both
begin
vLeft_tmp[vIndex] := vLeft[vCtrl[i].Idx_L];
vRight_tmp[vIndex] := vRight[vCtrl[i].Idx_R];
Inc(vIndex);
end;
if vCtrl[i].Side = sLeft then // Data from Left side
begin
vLeft_tmp[vIndex] := vLeft[vCtrl[i].Idx_L];
vRight_tmp[vIndex].BlankLine := true;
Inc(vIndex);
end;
if vCtrl[i].Side = sRight then // Data from Right side
begin
vRight_tmp[vIndex] := vRight[vCtrl[i].Idx_R];
vLeft_tmp[vIndex].BlankLine := true;
Inc(vIndex);
end;
end;
vLeft := vLeft_tmp;
vRight := vRight_tmp;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
i, vIndex: integer;
begin
PrepareData;
AlignArrays(aCtrl, aLeft, aRight);
end;
Question: Can this be better refactored and is it possible to work on the arrays without temp arrays?
EDIT:
From comments and answers it seems I waste too much time preparing MCVE, I should better explain the problem I have. But, from an CleoR's answer I got an idea to align arrays by starting in he last line and aligning to the top. Adn it seems to work, and here is why:
Because control array has instructions on how to align lines, I know exactly what the size of arrays is. And since aligning means 'stretchin' array/inserting new blank lines where needed, if I start from the bottom up, I don't need to insert anything, only move the lines that need to be moved.
Simple and it works - without temp arrays:
procedure AlignArraysBackwards(vCtrl: TArray<TCtrlData>; var vLeft, vRight: TArray<TData>);
var
i: integer;
vBlankRecord:TData;
begin
// set blank record to blank out the moved line
vBlankRecord.DataID:=0;
vBlankRecord.DataName:='';
vBlankRecord.BlankLine:=True;
// set lenght for arrays
SetLength(vLeft, Length(vCtrl));
SetLength(vRight, Length(vCtrl));
// align - starting from the bottom up
for i := High(vCtrl) downto 0 do
begin
if vCtrl[i].Side = sBoth then // Data from Both
begin
// move Left line
vLeft[i] := vLeft[vCtrl[i].Idx_L];
// blank out the line we just moved
if vCtrl[i].Idx_L<>i then vLeft[vCtrl[i].Idx_L]:=vBlankRecord;
// move Rigth line
vRight[i] := vRight[vCtrl[i].Idx_R];
// blank out the line we copied from
if vCtrl[i].Idx_R<>i then vRight[vCtrl[i].Idx_R]:=vBlankRecord;
end;
if vCtrl[i].Side = sLeft then // Data from Left side
begin
// move Left line
vLeft[i] := vLeft[vCtrl[i].Idx_L];
// blank out the line we just moved
if vCtrl[i].Idx_L<>i then vLeft[vCtrl[i].Idx_L]:=vBlankRecord;
// blank Right line
vRight[i].BlankLine := true;
end;
if vCtrl[i].Side = sRight then // Data from Right side
begin
// move Left line
vRight[i] := vRight[vCtrl[i].Idx_R];
// blank out the line we just moved
if vCtrl[i].Idx_R<>i then vRight[vCtrl[i].Idx_R]:=vBlankRecord;
// blank Left line
vLeft[i].BlankLine := true;
end;
end;
end;
UPDATE: Changed the solution to pseudocode.
You don't need a temp array, you can do it in place.
Lets assume the left and right arrays have enough space and they are the same size.
For each array you'll need to keep track of the last element in the array. Lets call this the dataPointer. Reverse loop over the arrays with a counter called endPointer.
At each step in the loop check if array[dataPointer] == endPointer + minElement for both arrays.
If true, array[endPointer] = endPointer + minElement and decrement the dataPointer.
If false, array[endPointer] = skip_value.
Do this until endPointer goes past the beginning of the array.
skip_value = 0
//Handles our assumptions.
function setup(left,right)
left.sort()
right.sort()
ldPointer = len(left)-1
rdPointer = len(right)-1
maxElement = max(left[ldPointer],right[rdPointer])
//This is 1 in your examples. You can hard code this number.
minElement = min(left[0],right[0])
padLength = maxElement - minElement + 1
pad(left,padLength)
pad(right,padLength)
return ldPointer,rdPointer,minElement
//Aligns the arrays.
function align(left,right)
ldPointer,rdPointer,minElement = setup(left,right)
for endPointer = len(left)-1; endPointer >= 0; i--
//Look at the left element.
if left[ldPointer] == endPointer+minElement
left[endPointer] = endPointer+minElement
ldPointer = ldPointer - 1
else
left[endPointer] = skip_value
//Look at the right element.
if right[rdPointer] == endPointer+minElement
right[endPointer] = endPointer+minElement
rdPointer = rdPointer - 1
else
right[endPointer] = skip_value
In case you want to try the algorithm out for yourself, heres a link to the repo. https://github.com/cleor41/StackOverflow_AlignArrays.
I don't know an ounce of Delphi but I tried to write it in Delphi so maybe you can understand it better. I also don't understand the need to have the control array.
procedure AlignArraysBackwards(var vLeft, vRight: TArray<TData>);
var
endPointer: Integer;
vBlankRecord: TData;
// Assumes the arrays have at least 1 element
ldPointer: Length(vLeft)-1;
rdPointer: Length(vRight)-1;
maxElement: Max(vLeft[ldPointer].DataID,vRight[rdPointer].DataID);
// Set this to 1 if arrays should always be 1 alligned
// Else it aligns arrays starting from the array with the smallest value.
minElement: Min(vLeft[0].DataID,vRight[0].DataID);
padLength: maxElement - minElement + 1;
begin
// set blank record to blank out the moved line
vBlankRecord.DataID:=0;
vBlankRecord.DataName:='';
vBlankRecord.BlankLine:=True;
// set length for arrays
SetLength(vLeft, padLength);
SetLength(vRight, padLength);
// align - starting from the bottom up
for endPointer := High(vLeft) downto 0 do
begin
// Start Left array
if vLeft[ldPointer].DataID = endPointer + minElement
then
begin
vLeft[endPointer] := vLeft[ldPointer];
ldPointer := ldPointer - 1;
end
else
begin
vLeft[endPointer] := vBlankRecord;
end;
// End Left Array
// Start Right array
if vRight[rdPointer].DataID = endPointer + minElement
then
begin
vRight[endPointer] := vRight[rdPointer];
rdPointer := rdPointer - 1;
end
else
begin
vRight[endPointer] := vBlankRecord;
end;
// End Right Array
end;
end;
You can make a method that will insert the records in the array or (as in my sample) you can use generics (TList).
program Project1;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
Generics.Collections;
type
TData = record
DataID: integer;
DataName: string;
BlankLine: boolean;
// I add this function to make it make the code easier to read
class function New(const DataID: integer; DataName: string;
BlankLine: boolean = false): TData; static;
end;
var
aLeft, aRight: TList<TData>;
{ TData }
class function TData.New(const DataID: integer; DataName: string;
BlankLine: boolean = false): TData;
begin
result.DataID := DataID;
result.DataName := DataName;
result.BlankLine := BlankLine;
end;
procedure AllignData;
var
n: word;
begin
n := 0;
repeat
if (n < aRight.Count) and (n < aLeft.Count) then
begin
if aLeft[n].DataID < aRight[n].DataID then
aRight.Insert(n, TData.New(aLeft[n].DataID, '', true))
else if aLeft[n].DataID > aRight[n].DataID then
aLeft.Insert(n, TData.New(aRight[n].DataID, '', true));
// if they are equlal, we skip the line
// you wish to use an array instead, write a function inserting data item in it
end
else
begin
if n < aLeft.Count then
aRight.Add(TData.New(aRight[n].DataID, '', true));
if n < aRight.Count then
aLeft.Add(TData.New(aRight[n].DataID, '', true));
end;
inc(n);
until (n >= aRight.Count) and (n >= aLeft.Count);
end;
procedure OutputData;
var
n: word;
sl, sr: string;
begin
n := 0;
repeat
if n < aLeft.Count then
sl := aLeft[n].DataName
else
sl := '';
if n < aRight.Count then
sr := aRight[n].DataName
else
sr := '';
writeln(sl: 15, sr: 15);
inc(n);
until (n >= aRight.Count) and (n >= aLeft.Count);
end;
begin
// Initialize the data
aLeft := TList<TData>.Create;
aRight := TList<TData>.Create;
try
aLeft.Add(TData.New(1, 'One'));
aLeft.Add(TData.New(3, 'Three'));
aLeft.Add(TData.New(6, 'Six'));
aLeft.Add(TData.New(8, 'Eight'));
aRight.Add(TData.New(1, 'One'));
aRight.Add(TData.New(2, 'Two'));
aRight.Add(TData.New(4, 'Four'));
aRight.Add(TData.New(5, 'Five'));
aRight.Add(TData.New(7, 'Seven'));
aRight.Add(TData.New(8, 'Eight'));
aRight.Add(TData.New(9, 'Nine'));
aRight.Add(TData.New(10, 'Ten'));
// Do the output and processing
OutputData;
// I assume that the arrays (lists) have been sorted
AllignData;
writeln;
OutputData
finally
aLeft.Free;
aRight.Free;
end;
readln;
end.
I have an array of integer and string fields. To make it distinct I currently copy line by line into new array and with each record I check if the record already exists in new, if not I copy it. At the end I copy new array back to original.
It works, but is slow. Is there any faster, easier way to do this?
TArrayMixed = record
Field1: integer;
Field2: integer;
Field3: integer;
Field4: string;
Field5: string;
Field6: string;
end;
procedure TForm1.Button10Click(Sender: TObject);
var
ArrayMixed, ArrayMixed_tmp: array of TArrayMixed;
i, j, vIdx: integer;
vExists: boolean;
begin
SetLength(ArrayMixed, 100000);
for i := 0 to 99999 do
begin
ArrayMixed[i].Field1 := 1 + Random(5);
ArrayMixed[i].Field2 := 1 + Random(5);
ArrayMixed[i].Field3 := 1 + Random(5);
ArrayMixed[i].Field4 := 'String';
ArrayMixed[i].Field5 := 'Another string';
ArrayMixed[i].Field6 := 'New string';
end;
// Sort
TArray.Sort<TArrayMixed > (ArrayMixed, TComparer<TArrayMixed > .Construct(function(const Left, Right: TArrayMixed): Integer
begin
Result := MyCompareAMixed(Left, Right);
end
));
// Distinct
SetLength(ArrayMixed_tmp, Length(ArrayMixed));
vIdx := 0;
for i := Low(ArrayMixed) to High(ArrayMixed) do
begin
vExists := False;
for j := Low(ArrayMixed_tmp) to vIdx - 1 do
if (ArrayMixed_tmp[j].Field1 = ArrayMixed[i].Field1) and
(ArrayMixed_tmp[j].Field2 = ArrayMixed[i].Field2) and
(ArrayMixed_tmp[j].Field3 = ArrayMixed[i].Field3) and
(ArrayMixed_tmp[j].Field4 = ArrayMixed[i].Field4) and
(ArrayMixed_tmp[j].Field5 = ArrayMixed[i].Field5) and
(ArrayMixed_tmp[j].Field6 = ArrayMixed[i].Field6) then
begin
vExists := True;
Break;
end;
if not vExists then
begin
ArrayMixed_tmp[vIdx] := ArrayMixed[i];
Inc(vIdx);
end;
end;
SetLength(ArrayMixed_tmp, vIdx);
// now copy back to original array
SetLength(ArrayMixed, 0);
SetLength(ArrayMixed, Length(ArrayMixed_tmp));
for i := Low(ArrayMixed_tmp) to High(ArrayMixed_tmp) do
ArrayMixed[i] := ArrayMixed_tmp[i];
sleep(0);
end;
Edit:
Since in real data the strings are not all the same, the part where it makes distinct array is slower when original array is filled like this:
Edit #2: (copied wrong code in Edit #1)
for i := 0 to 999999 do
begin
ArrayMixed[i].Field1 := 1 + Random(5);
ArrayMixed[i].Field2 := 1 + Random(5);
ArrayMixed[i].Field3 := 1 + Random(5);
ArrayMixed[i].Field4 := 'String'+IntToStr(i mod 5);
ArrayMixed[i].Field5 := 'Another string'+IntToStr(i mod 5);
ArrayMixed[i].Field6 := 'New string'+IntToStr( i mod 5);
end;
Edit #3: Publishing code for sorting - only first 3 fields are sorted!
TMyArray3 = array[1..3] of Integer;
function CompareIntegerArray3(const lhs, rhs: TMyArray3): Integer;
var
i: Integer;
begin
Assert(Length(lhs) = Length(rhs));
for i := low(lhs) to high(lhs) do
if lhs[i] < rhs[i] then
exit(-1)
else if lhs[i] > rhs[i] then
exit(1);
exit(0);
end;
function GetMyArrayAMixed(const Value: TArrayMixed): TMyArray3;
begin
Result[1] := Value.Field1;
Result[2] := Value.Field2;
Result[3] := Value.Field3;
end;
function MyCompareAMixed(const lhs, rhs: TArrayMixed): Integer;
begin
Result := CompareIntegerArray3(GetMyArrayAMixed(lhs), GetMyArrayAMixed(rhs));
end;
Implement some methods (equality check, hashcode) for the record to get away with a lot of boilerplate code
type
TArrayMixed = record
Field1: integer;
Field2: integer;
Field3: integer;
Field4: string;
Field5: string;
Field6: string;
class operator Equal( const a, b: TArrayMixed ): Boolean;
class function Compare( const L, R: TArrayMixed ): integer; overload; static;
function Compare( const Other: TArrayMixed ): integer; overload;
function GetHashCode( ): integer;
end;
{ TArrayMixed }
class function TArrayMixed.Compare( const L, R: TArrayMixed ): integer;
begin
Result := L.Compare( R );
end;
function TArrayMixed.Compare( const Other: TArrayMixed ): integer;
begin
Result := Field1 - Other.Field1;
if Result = 0
then
begin
Result := Field2 - Other.Field2;
if Result = 0
then
begin
Result := Field3 - Other.Field3;
if Result = 0
then
begin
Result := CompareStr( Field4, Other.Field4 );
if Result = 0
then
begin
Result := CompareStr( Field5, Other.Field5 );
if Result = 0
then
begin
Result := CompareStr( Field6, Other.Field6 );
end;
end;
end;
end;
end;
end;
class operator TArrayMixed.Equal( const a, b: TArrayMixed ): Boolean;
begin
Result := true
{} and ( a.Field1 = b.Field1 )
{} and ( a.Field2 = b.Field2 )
{} and ( a.Field3 = b.Field3 )
{} and ( a.Field4 = b.Field4 )
{} and ( a.Field5 = b.Field5 )
{} and ( a.Field6 = b.Field6 );
end;
function TArrayMixed.GetHashCode: integer;
begin
{$IFOPT Q+}
{$Q-}
{$DEFINE SET_Q_ON}
{$ENDIF}
Result := 17;
Result := Result * 31 + Field1;
Result := Result * 31 + Field2;
Result := Result * 31 + Field3;
Result := Result * 31 + Field4.GetHashCode;
Result := Result * 31 + Field5.GetHashCode;
Result := Result * 31 + Field6.GetHashCode;
{$IFDEF SET_Q_ON}
{$Q+}
{$UNDEF SET_Q_ON}
{$ENDIF}
end;
Use a TDictionary as a HashSet to check for duplicates
procedure Test;
var
arr1, arr2: TArray<TArrayMixed>;
idx : integer;
lst : TDictionary<TArrayMixed, integer>;
begin
// fill the array
SetLength( arr1, 100000 );
for idx := low( arr1 ) to high( arr1 ) do
begin
arr1[ idx ].Field1 := 1 + Random( 5 );
arr1[ idx ].Field2 := 1 + Random( 5 );
arr1[ idx ].Field3 := 1 + Random( 5 );
arr1[ idx ].Field4 := 'String' + IntToStr( idx mod 5 );
arr1[ idx ].Field5 := 'Another string' + IntToStr( idx mod 5 );
arr1[ idx ].Field6 := 'New string' + IntToStr( idx mod 5 );
end;
// distinct
lst := TDictionary<TArrayMixed, integer>.Create( TEqualityComparer<TArrayMixed>.Construct(
function( const L, R: TArrayMixed ): Boolean
begin
Result := ( L = R );
end,
function( const i: TArrayMixed ): integer
begin
Result := i.GetHashCode( );
end ) );
try
for idx := low( arr1 ) to high( arr1 ) do
begin
lst.AddOrSetValue( arr1[ idx ], 0 );
end;
arr2 := lst.Keys.ToArray;
finally
lst.Free;
end;
end;
I would do something like this. You basically create the result on the fly and sort at the same time using a binary search to remove the duplicates.
function RemoveDuplicates(aSourceArray: TArray<TArrayMixed>): TArray<TArrayMixed>;
var
i: Integer;
index: Integer;
sortList: TList<TArrayMixed>;
begin
sortList := TList<TArrayMixed>.Create;
try
for i := Low(aSourceArray) to High(aSourceArray) do
begin
if not sortList.BinarySearch(aSourceArray[i], index,
TDelegatedComparer<TArrayMixed>.Construct(
function(const L, R: TArrayMixed): integer
begin
Result := L.Field1 - R.Field1;
if Result <> 0 then Exit;
Result := L.Field2 - R.Field2;
if Result <> 0 then Exit;
Result := L.Field3 - R.Field3;
if Result <> 0 then Exit;
Result := CompareStr(L.Field4, R.Field4);
if Result <> 0 then Exit;
Result := CompareStr(L.Field5, R.Field5);
if Result <> 0 then Exit;
Result := CompareStr(L.Field6, R.Field6);
end)) then
begin
sortList.Insert(index, aSourceArray[i]);
end;
end;
Result := sortList.ToArray;
finally
sortList.Free;
end;
end;
To use this code you could do something like this:
procedure TForm1.Button10Click(Sender: TObject);
var
ArrayMixed, ArrayMixed_tmp: TArray<TArrayMixed>;
i: Integer;
begin
SetLength(ArrayMixed, 100000);
for i := 0 to 999999 do
begin
ArrayMixed[i].Field1 := 1 + Random(5);
ArrayMixed[i].Field2 := 1 + Random(5);
ArrayMixed[i].Field3 := 1 + Random(5);
ArrayMixed[i].Field4 := 'String'+IntToStr(i mod 5);
ArrayMixed[i].Field5 := 'Another string'+IntToStr(i mod 5);
ArrayMixed[i].Field6 := 'New string'+IntToStr( i mod 5);
end;
ArrayMixed_tmp := RemoveDuplicates(ArrayMixed);
end;
Just check for duplicates next to the prior index, since the array is sorted. Here is the sorting comparer reused as well.
function RemoveDuplicates(const anArray: array of TArrayMixed): TArray<TArrayMixed>;
var
j, vIdx: integer;
begin
// Sort
TArray.Sort<TArrayMixed > (anArray, TComparer<TArrayMixed >.Construct(function(const Left, Right: TArrayMixed): Integer
begin
Result := MyCompareAMixed(Left, Right);
end
));
// Distinct
SetLength(Result, Length(anArray));
vIdx := 0;
j := 0;
while (j <= High(anArray) do
begin
Result[vIdx] := anArray[j];
Inc(j);
While (j <= High(anArray)) and (MyCompareAMixed(Result[vIdx],anArray[j]) = 0) do
Inc(j);
Inc(vIdx);
end;
SetLength(Result, vIdx);
end;
Update:
In an update to the question it is stated that the array is only partially sorted. One way to reduce the number of iterations to remove duplicates would then be to:
Find start and stop index to items that share the first sorting criteria.
Iterate among them to sort out duplicates.
Since you already sort ArrayMixed you don't need to compare each item with each other in order to find duplicates. The duplicates are already placed next to each other. So you simply need to iterate over ArrayMixed and compare the current item to the last item in ArrayMixed_tmp.
Hence, copying the distinct items can be proceed much faster and looks like that:
vIdx := 0;
for i := Low(ArrayMixed) to High(ArrayMixed) do
begin
if (vIdx = 0) or // the first item can never be a duplicate
(ArrayMixed_tmp[vIdx].Field1 <> ArrayMixed[i].Field1) or
(ArrayMixed_tmp[vIdx].Field2 <> ArrayMixed[i].Field2) or
(ArrayMixed_tmp[vIdx].Field3 <> ArrayMixed[i].Field3) or
(ArrayMixed_tmp[vIdx].Field4 <> ArrayMixed[i].Field4) or
(ArrayMixed_tmp[vIdx].Field5 <> ArrayMixed[i].Field5) or
(ArrayMixed_tmp[vIdx].Field6 <> ArrayMixed[i].Field6) then
begin
ArrayMixed_tmp[vIdx] := ArrayMixed[i];
Inc(vIdx);
end;
end;
You have not posted the code for your MyCompareAMixed() function so it is not possible to test the performance of your actual code including this undefined function, including the current sort performance.
However, since your posted duplicate detection approach is not dependent upon the array being sorted I simply removed the sort from the code.
Without any further optimisation the resulting de-duplication process completed in well under 50 msecs, which is not "slow" in my book for de-duping 100,000 complex items. i.e. not single values but items that are records of multiple values.
If the sort is necessary for other reasons then you could retain the sorting and optimise the de-dupe process based on the answers given by others, but I would first question why you think the process is slow and if sub 50 msecs really is slow, what is the target you are aiming at ?
It is possible that it is the sorting that is adding the overhead (as I say, without your compare function we cannot quantify the overhead this is adding) so if this sorting is not necessary for other reasons and if sub 50-msecs is acceptable for de-duping this array, then I would move on to other tasks.
I have an array of byte that I wish to convert into a hex string, and then back into an array of byte.
I am using the following to convert into a hex string:
function bintoHex(const bin: array of byte): String;
const HexSymbols = '0123456789ABCDEF';
var i: integer;
begin
SetLength(Result, 2*Length(bin));
for i := 0 to Length(bin)-1 do begin
Result[1 + 2*i + 0] := HexSymbols[1 + bin[i] shr 4];
Result[1 + 2*i + 1] := HexSymbols[1 + bin[i] and $0F];
end;
end;
I am unsure how to convert it back into an array of byte properly. I am shooting for something like the following:
Type TDCArray = Array of Byte;
function xHexToBin(const HexStr: String): TDCArray;
const HexSymbols = '0123456789ABCDEF';
var i: integer;
begin
SetLength(Result, ???); //Need to now get half of the length, unsure how to go about that
for i := 0 to Length(HexStr)-1 do begin
//Here convert back into an array somehow...
//Result[i] := ???
end;
end;
How would I go about doing this?
Also, I am using Delphi XE2.
Why not just use the BinToHex and HexToBin RTL functions?
{$APPTYPE CONSOLE}
uses
System.Classes,
System.SysUtils;
var
LArray : array[1..6] of Byte = (10, 11, 12, 13, 14, 15);
LText: string;
I : integer;
begin
try
SetLength(LText, Length(LArray)*2);
BinToHex(#LArray, PChar(LText), SizeOf(LArray));
//show the hex string
Writeln(LText);
//fill the array with 0
FillChar(LArray, SizeOf(LArray), #0);
//get the values from the hex string
HexToBin(PChar(LText), #LArray, Length(LArray));
//show the array values
for i := 1 to Length(LArray) do
Write(LArray[i]);
Readln;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
end.
If you want to do it yourself:
function xHexToBin(const HexStr: String): TBytes;
const HexSymbols = '0123456789ABCDEF';
var i, J: integer;
B: Byte;
begin
SetLength(Result, (Length(HexStr) + 1) shr 1);
B:= 0;
i := 0;
while I < Length(HexStr) do begin
J:= 0;
while J < Length(HexSymbols) do begin
if HexStr[I + 1] = HexSymbols[J + 1] then Break;
Inc(J);
end;
if J = Length(HexSymbols) then ; // error
if Odd(I) then
Result[I shr 1]:= B shl 4 + J
else
B:= J;
Inc(I);
end;
if Odd(I) then Result[I shr 1]:= B;
end;
2 hex chars represent 1 byte
The code i wrote earlier was pseudocode I wanted you to get the ideea. But if you need some code to paste here is the actual implementation:
program project1;
uses SysUtils,classes;
type
TByteArray = array of byte;
function StrToArray(const Hexstr: String): TByteArray ;
var
i: Integer;
begin
SetLength(Result, Length(Hexstr) div 2);
for i:=0 to (Length(Hexstr) div 2 - 1) do
Result[i]:= StrToInt('$' + Copy(Hexstr, (i * 2) + 1, 2));
end;
var
arr : TByteArray;
i : Integer;
begin
arr := StrToArray('0A0B0C0D');
for i:=0 to High(arr) do
WriteLn(arr[i]);
Readln;
end.
Btw coding is not about cuting and pasting ;)
unit Unit1;
{$mode objfpc}{$H+}
interface
uses
SysUtils, Forms, StdCtrls, ExtCtrls, Classes;
type
{ TTextToHex_HexToBin }
TTextToHex_HexToBin = class(TForm)
Button1: TButton;
Edit1: TEdit;
Edit2: TEdit;
CheckTime: TImage;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Label4: TLabel;
Memo1: TMemo;
procedure Button1Click(Sender: TObject);
procedure CheckTimeClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
end;
var
TextToHex_HexToBin: TTextToHex_HexToBin;
implementation
{$R *.lfm}
{ TTextToHex_HexToBin }
//hex to binary
function HextoBinary(const AHexStr: string):string;
var
i, j: Integer;
const
HexParts: array[0..$F] of string =
(
{0} '0000',{1} '0001',{2} '0010',{3} '0011',{4} '0100',{5} '0101',{6} '0110',{7} '0111',
{8} '1000',{9} '1001',{A} '1010',{B} '1011',{C} '1100',{D} '1101',{E} '1110',{F} '1111'
);
begin
SetLength(Result, 4 * AHexStr.Length);
j := 1;
for i := 1 to AHexStr.Length do
begin
case AHexStr[i] of
'0'..'9':
Move(HexParts[Ord(AHexStr[i]) - Ord('0')][1], Result[j], sizeof(char) * 4);
'A'..'F':
Move(HexParts[$A + Ord(AHexStr[i]) - Ord('A')][1], Result[j], sizeof(char) * 4);
'a'..'f':
Move(HexParts[$A + Ord(AHexStr[i]) - Ord('a')][1], Result[j], sizeof(char) * 4);
else
raise EConvertError.CreateFmt('Invalid hexadecimal string "%s".', [AHexStr]);
end;
Inc(j, 4);
end;
end;
procedure TTextToHex_HexToBin.Button1Click(Sender: TObject);
var
TB: TBytes;
WS: WideString;
S: string;
i: Integer;
begin
WS := Trim(Edit1.Caption);
TB := WideBytesOf(WS);
// WideString to Hexadecimal
S := '';
for i := Low(TB) to High(TB) do
S := S + IntToHex(TB[i], -1);
Edit2.Caption :=Trim(S);
// Hex to Binary
Memo1.Caption:= HextoBinary(Trim(S));
end;
procedure TTextToHex_HexToBin.CheckTimeClick(Sender: TObject);
begin
end;
procedure TTextToHex_HexToBin.FormCreate(Sender: TObject);
begin
end;
end.
[Result Show as Below]