Tracey
Stylistic really I also finding typing pred(Count) is less error
prone the - 1 sometimes gets lost
N
----- Original Message -----
From: "Tracey Maule" <[EMAIL PROTECTED]>
To: "Multiple recipients of list delphi" <[EMAIL PROTECTED]>
Sent: Friday, November 01, 2002 10:48 AM
Subject: Re: [DUG]: Friday Challange
Just as an aside, could u tell me why u are all using pred(itemcount)
instead of (itemcount - 1)????
----- Original Message -----
From: Stephen Bertram
To: Multiple recipients of list delphi
Sent: Friday, November 01, 2002 9:38 AM
Subject: RE: [DUG]: Friday Challange
I've done this in 5 different ways. One of the more flexible is
function statement(Sep, Quote: String): string;
var
I: integer;
begin
Result := Sep;
for I := 0 to pred(ItemCount) do
Result := format('%s%s%s%s%s',[Result,Sep,Quote,Item[I],Quote])
Delete(Result, 1, Length(Sep);
end;
The main advantage of this is speed where the list is large - the
conditional is removed from the iteration.
(Note that many variants of SQL limit the number of parameters in a list to
255 and the length of the list to 2000 or 4000.)
One of our standard method for comma separated lists is to use a stringlist
(not efficient but simple and avoids empty lists):
function statement(FieldName, EmptyCondition: String; Quote: Boolean):
string;
var
i integer;
ResList : TStringList;
begin
ResList := TStringList.Create;
for I := 0 to pred(ItemCount) do
if Quote
ResList.Add(Format('''%s''',[Item[i]]))
else
ResList.Add(Item[i]);
if ResList.Count > 0 then
Result := Format('%s in (%s)',[FieldName, ResList.CommaText]
else
Result := EmptyCondition;
ResList.Free;
end;
Result := $0.02;
Stephen
-----Original Message-----
From: Neven MacEwan [mailto:neven@;mwk.co.nz]
Sent: Friday, 1 November 2002 12:28 a.m.
To: Multiple recipients of list delphi
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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