I think you can safely assume that an SQL query will have less than 100 or
so joins, so no need for string buffers. Perhaps the *REAL* Friday
challenge is to come with an SQL statement with > 100 joins!
Dennis.
----- Original Message -----
From: "Neven MacEwan" <[EMAIL PROTECTED]>
To: "Multiple recipients of list delphi" <[EMAIL PROTECTED]>
Sent: Friday, November 01, 2002 10:03 AM
Subject: Re: [DUG]: Friday Challange
> Dennis
>
> Therein lies the challange, to come up with an efficient 'Join' procedure
> that
> require no preknowlege of iteration count or item length
>
> would the format be sominthing like
>
> TJoinItemFunction = function(Index: integer): string;
> TJoinOption = (joRemoveBlanks, joUnique, joCaseSensitive);
> TJoinOptions = set of TJoinOption;
>
> function Join(GetItem: TJoinItemFunction ; count: integer; const Sep:
> string, Options TJoinOptions): string;
>
> N
>
>
> ----- Original Message -----
> From: "Dennis Chuah" <[EMAIL PROTECTED]>
> To: "Multiple recipients of list delphi" <[EMAIL PROTECTED]>
> Sent: Friday, November 01, 2002 9:36 AM
> Subject: Re: [DUG]: Friday Challange
>
>
> >
> > It depends on the size of your loop. If you are going to be appeding a
> > great number of strings, then I would suggest a string buffer approach -
> > where each iteration of the loop writes one string into the string
buffer,
> > while an int variable is incremented with the length of the string.
Then
> > create a string with the length of the int. In another loop, take the
> > strings from the buffer and write to the allocated string.
> >
> > I have done tests with loops in sizes ranging from 10, 100, 1000,
through
> to
> > 1mil. The time savings for the 1mil loop is several oders of magnitude.
> I
> > won't bother for anything less than 100.
> >
> > Dennis.
> >
> > ----- Original Message -----
> > From: Neven MacEwan
> > To: Multiple recipients of list delphi
> > Sent: Friday, November 01, 2002 12:27 AM
> > Subject: [DUG]: Friday Challange
> >
> >
> > Hi all,
> >
> > Further to my enpty string question, I'm writing a lot of
> > functions that return a set of strings joined by a separator
> > ie 'col1, col2,...' or 'col1 = 'a' and colb = 'b'' (as you may guess
> > these are all parts of SQL Statements)
> >
> > given a function 'Itemcount' that returns the number of items
> > and item(i) that returns the item string, and function sep what is the
> > best form of such a function
> >
> > to seed the duscussion I'll give you one of my variants
> >
> > function statement: string;
> > var
> > I: integer;
> > begin
> > Result := '';
> > for I := 0 to pred(ItemCount) do
> > if I = 0 then Result := Item(I)
> > else Result := format('%s%s%s',[Result,Sep,Item(I)])
> > end;
> >
> > Variants and explainations pls
> >
> > Neven
>
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