Re: [fpc-pascal] Get highest element of a StringList

2022-09-12 Thread Martin Wynne via fpc-pascal 

On 12/09/2022 15:37, James Richters via fpc-pascal wrote:

So I could just do this?

Index:= MyStringlist.IndexOfName(SearchName);
If Index >=0 then
MyValue := MyStringlist[Index].ValueFromIndex;



Hi James,

I would probably do

try
  with MyStringList do MyValue:=ValueFromIndex[IndexOfName(SearchName)];
except
  MyValue:='';
end;

cheers,

Martin.
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Re: [fpc-pascal] Get highest element of a StringList

2022-09-12 Thread James Richters via fpc-pascal 
So I could just do this?

Index:= MyStringlist.IndexOfName(SearchName);
If Index >=0 then
   MyValue := MyStringlist[Index].ValueFromIndex;

That sure is nice to know, Thank you!

I guess for my dynamic arrays of records, I still need to search with a
loop... or is there a cool thing I don't know about for that as well?

James

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-12 Thread Martin Wynne via fpc-pascal 

On 12/09/2022 14:16, James Richters via fpc-pascal wrote:

The problem with the for in loop is that I need the index.


Hi James,

You don't need a loop for that:

 index:=MyStringlist.IndexOfName;

see: 
https://www.freepascal.org/docs-html/rtl/classes/tstrings.indexofname.html


martin.
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Re: [fpc-pascal] Get highest element of a StringList

2022-09-12 Thread James Richters via fpc-pascal 
The problem with the for in loop is that I need the index.

I'm sometimes searching through the stringlist looking for a match, and when I 
find a match, I want to read the value
And then do a break, because there is no point is searching once I found what I 
am looking for:

For I:= 0 to MyStringlist.high Do
   Begin
   If MyStringlist[I].Names = SearchName Then
  Begin
MyValue := MyStringlist[I].ValueFromIndex;
Break;
  End;
   End;

I agree that the for - in loop is a great way if you are always processing the 
entire list and don't need the index for anything.

James

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-12 Thread Peter B via fpc-pascal 

On 12/09/2022 07:52, Jean SUZINEAU via fpc-pascal wrote:

As Bart suggested, you can use too the for/in loop:  for s in sl do WriteLn( s);



And that is IMHO by far the most elegant, and least error prone, representation.

Cheers,
Peter
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Re: [fpc-pascal] Get highest element of a StringList

2022-09-11 Thread Jean SUZINEAU via fpc-pascal 
As Bart suggested, you can use too the for/in loop:  for s in sl do 
WriteLn( s);


For example:

var
   sl: TStringList;
   s: String;
begin
 sl:= TStringList.Create;
 try
    sl.Add('1');
    sl.Add('2');
    for s in sl do WriteLn( s);
 finally
    FreeAndNil( sl);
    end;
end.

Output:

1
2

This works on arrays and strings too.

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-11 Thread James Richters via fpc-pascal 
The loops is just an example because in my original post of why I wanted to
get the highest element of a stringlist was because I wanted a for loop that
wasn't as clumsy as

For I:=0 to myStringlist.count-1 Do

This came up because thanks to this discussion list, I learned I could use
High() and Low() for my dynamic arrays,  so I went through replacing all
instances of 

Length(MyDynamicArray)-1 with  High(MyDynamicArray)

So my for loops went from:

For I:=0 to Length(MyDynamicArray)-1 Do 
To 
For I:=0 to High(MyDynamicArray) Do

Which I find much more clear and less prone to problems.. I have forgot the
-1 before and it gives range check errors of course.. so I'm switching
everything to use High() instead and will just automatically use High() in
the future, thus preventing the issue all together.

I'm really happy with the helper function and using MyStringList.High.  I
think .High should just be added to all things that have a .Count because
everyone always needs it ALL THE TIME.  But I am happy it's possible to add
a helper function to add it myself.

James

>Why the loop?

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-11 Thread Sven Barth via fpc-pascal 
James Richters via fpc-pascal  schrieb am
Sa., 10. Sep. 2022, 22:55:

>
> For some reason
> {$Mode FPC}
> {$modeswitch typehelpers}
> Still had Error: Identifier not found "class"
>

Because support for the "class" keyword is only available when the
modeswitch Class is enabled which is the case for the ObjFPC and Delphi
modes.
You don't need the TypeHelpers mode switch for "class helper", only for
"type helper".

Regards,
Sven

>
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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Travis Siegel via fpc-pascal 
But, if that (eventually) leads to the highest one, and that's all 
that's desired, why not just use the whole expression variable := 
pred(f.Count) instead of the whole loop?


Wouldn't that accomplish the same thing?

Why the loop?


On 9/10/2022 3:44 PM, Thomas Kurz via fpc-pascal wrote:

If you just don't like the "-1" for readability, you might also wan't to 
consider using

for i := 0 to Pred(f.Count) do ...


- Original Message -
From: Thomas Kurz via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 21:37:34
Subject: [fpc-pascal] Get highest element of a StringList

Try this (note the "modeswitch"):

program Project1;

{$modeswitch typehelpers}

uses
   Classes,
   SysUtils;

type TStringListHelper = class helper for TStringList
   function High: NativeInt;
end;

function TStringListHelper.High: NativeInt;
begin
   Exit (Self.Count-1);
end;

var
   f: TStringList = nil;
   i: Integer;

begin
   f := TStringList.Create;
   f.Add ('hallo');
   f.Add ('welt');
   f.Add ('!');
   for i := 0 to f.High do Writeln (f[i]);
   FreeAndNil (f);
end.





- Original Message -
From: James Richters via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 19:57:51
Subject: [fpc-pascal] Get highest element of a StringList

This Helper sounds like a nice way to do it.  I need the numerical index of
the loop so this would be more straight forward.
Would I then do something like :
For I:= 0 to MyStringList.High Do
?

When I try to add the Type statement:
type TStringListHelper = class helper for TStringList function High:
NativeInt; end;
I getError: Identifier not found "class"

I have the Classes unit.  Is there something else I am missing?

James


Another alternative would be declaring a helper:
type TStringListHelper = class helper for TStringList function High:

NativeInt; end;


function TStringListHelper.High: NativeInt; begin
  Exit (Self.Count-1);
end;

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Martin Wynne via fpc-pascal 

On 10/09/2022 17:01, James Richters via fpc-pascal wrote:


For Loop := 0 to MyStringList.Count-1 do

It would be nice to not have the -1


I don't understand what is wrong with Count-1, but you can get the 
highest index like this if you wish:


high_index:=Length(Trim(MyStringList.Text))-Length(StringReplace(Trim(MyStringList.Text),#13,'',[rfReplaceAll]));

Martin.
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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread James Richters via fpc-pascal 
Thank you for the example! I also needed 

{$Mode OBJFPC}  

to get it working.  I am normally in
{$Mode FPC} Or {$Mode TP}
But I found that if I just put this in a unit that is {$Mode OBJFPC} and
include that unit in my {$Mode TP} Unit it works just great!

I have a useless unit that is just a whole list of constants, types, and
variables used by my other units, just so I don't have to scroll past over
1000 lines of code just to get to the functions and procedures.
It was {$Mode FPC}

For some reason
{$Mode FPC}
{$modeswitch typehelpers}
Still had Error: Identifier not found "class"

So I changed it to 
{$Mode OBJFPC}
{$modeswitch typehelpers}
And put the function in it, and it's working great!

My main reason for wanting something like this is because I occasionally
will forget the -1 and... well... that's no good...
Since I recently learned of High() and Low() for arrays, I've been changing
all my for loops with arrays to use High() and sometimes Low() if they don't
start at 0.  It's also helpful to do something like:

MyArray[High(MyArray)] := something;  

To write to a newly added array element where I used to have

MyArray[Length(MyArray)-1] := something;  

While it does work.. it's less readable and prone to errors.

James

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Thomas Kurz via fpc-pascal 
If you just don't like the "-1" for readability, you might also wan't to 
consider using

for i := 0 to Pred(f.Count) do ...


- Original Message - 
From: Thomas Kurz via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 21:37:34
Subject: [fpc-pascal] Get highest element of a StringList

Try this (note the "modeswitch"):

program Project1;

{$modeswitch typehelpers}

uses
  Classes,
  SysUtils;

type TStringListHelper = class helper for TStringList
  function High: NativeInt;
end;

function TStringListHelper.High: NativeInt;
begin
  Exit (Self.Count-1);
end;

var
  f: TStringList = nil;
  i: Integer;

begin
  f := TStringList.Create;
  f.Add ('hallo');
  f.Add ('welt');
  f.Add ('!');
  for i := 0 to f.High do Writeln (f[i]);
  FreeAndNil (f);
end.





- Original Message - 
From: James Richters via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 19:57:51
Subject: [fpc-pascal] Get highest element of a StringList

This Helper sounds like a nice way to do it.  I need the numerical index of
the loop so this would be more straight forward.
Would I then do something like :
For I:= 0 to MyStringList.High Do 
?

When I try to add the Type statement:
type TStringListHelper = class helper for TStringList function High:
NativeInt; end;
I getError: Identifier not found "class"

I have the Classes unit.  Is there something else I am missing?

James

>Another alternative would be declaring a helper:

>type TStringListHelper = class helper for TStringList function High:
NativeInt; end;

>function TStringListHelper.High: NativeInt; begin
>  Exit (Self.Count-1);
>end;

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Thomas Kurz via fpc-pascal 
Try this (note the "modeswitch"):

program Project1;

{$modeswitch typehelpers}

uses
  Classes,
  SysUtils;

type TStringListHelper = class helper for TStringList
  function High: NativeInt;
end;

function TStringListHelper.High: NativeInt;
begin
  Exit (Self.Count-1);
end;

var
  f: TStringList = nil;
  i: Integer;

begin
  f := TStringList.Create;
  f.Add ('hallo');
  f.Add ('welt');
  f.Add ('!');
  for i := 0 to f.High do Writeln (f[i]);
  FreeAndNil (f);
end.





- Original Message - 
From: James Richters via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 19:57:51
Subject: [fpc-pascal] Get highest element of a StringList

This Helper sounds like a nice way to do it.  I need the numerical index of
the loop so this would be more straight forward.
Would I then do something like :
For I:= 0 to MyStringList.High Do 
?

When I try to add the Type statement:
type TStringListHelper = class helper for TStringList function High:
NativeInt; end;
I getError: Identifier not found "class"

I have the Classes unit.  Is there something else I am missing?

James

>Another alternative would be declaring a helper:

>type TStringListHelper = class helper for TStringList function High:
NativeInt; end;

>function TStringListHelper.High: NativeInt; begin
>  Exit (Self.Count-1);
>end;

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread James Richters via fpc-pascal 
This Helper sounds like a nice way to do it.  I need the numerical index of
the loop so this would be more straight forward.
Would I then do something like :
For I:= 0 to MyStringList.High Do 
?

When I try to add the Type statement:
type TStringListHelper = class helper for TStringList function High:
NativeInt; end;
I getError: Identifier not found "class"

I have the Classes unit.  Is there something else I am missing?

James

>Another alternative would be declaring a helper:

>type TStringListHelper = class helper for TStringList function High:
NativeInt; end;

>function TStringListHelper.High: NativeInt; begin
>  Exit (Self.Count-1);
>end;

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Thomas Kurz via fpc-pascal 
Another alternative would be declaring a helper:

type TStringListHelper = class helper for TStringList
function High: NativeInt;
end;

function TStringListHelper.High: NativeInt;
begin
  Exit (Self.Count-1);
end;


- Original Message - 
From: James Richters via fpc-pascal 
To: 'FPC-Pascal users discussions' 
Sent: Saturday, September 10, 2022, 18:01:20
Subject: [fpc-pascal] Get highest element of a StringList

I thought I would try:

For Loop := 0 to High(MyStringList) do

But I get "Error: Type mismatch"

Is there a way to get the highest element of a stringlist other than:

For Loop := 0 to MyStringList.Count-1 do

It would be nice to not have the -1
Could High() be made to work if the argument was a stringlist?

James

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Re: [fpc-pascal] Get highest element of a StringList

2022-09-10 Thread Bart via fpc-pascal 
On Sat, Sep 10, 2022 at 6:01 PM James Richters via fpc-pascal
 wrote:

> Is there a way to get the highest element of a stringlist other than:
>
> For Loop := 0 to MyStringList.Count-1 do

You can use the for .. in loop.


> It would be nice to not have the -1
> Could High() be made to work if the argument was a stringlist?

Probabaly it could, but it's not likely going to happen.


-- 
Bart
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