Re: Checking a set of strings
Joanna Carter (TeamB)
4296d3d2$1...@newsgroups.borland.com...
> I have tried to set an Array of string.
> CGases : Array of String;
> But when I set
> CGases[0] := 'ACETYLENE'; I get an error.
You are geting an error because you have not set the length of the array
before using it.
> I have also tried using TStringlist component with no luck. I have checked
out the help files but I have not seen direction on how to do this.
Try this
var
strs: TStrings;
begin
strs := TStringList.Create;
try
if strs.IndexOf(testStr) > -1 then
// testStr is in the list
...
finally
strs.Free;
end;
Joanna
--
Joanna Carter (TeamB)
Consultant Software Engineer
TeamBUG support for UK-BUG
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Tom Dalton
Hi,
I have try a few ways to do this but I seem to be comming up with dead ends!
I have a set of strings ['ACELYLENE','ETHANE','ETHYLENE',etc] now I would like test them against a variable that is obtained from another source.
So we can go the route of:
IF (Comp = 'ACETYLENE') or (Comp = 'ETHANE') or .... then
But is there a better method of checking whether Comp is in the set of parameters?
I have tried to set an Array of string.
CGases : Array of String;
But when I set
CGases[0] := 'ACETYLENE'; I get an error.
I have also tried using TStringlist component with no luck. I have checked out the help files but I have not seen direction on how to do this.
Regards
Tom Dalton
Anders Isaksson
<joa...@nospam.co.uk> wrote:
>Try this
>
>var
> strs: TStrings;
>begin
> strs := TStringList.Create;
strs.Text := 'ACELYLENE'#10'ETHANE'#10'ETHYLENE'#10...';
> try
> if strs.IndexOf(testStr) > -1 then
> // testStr is in the list
> ...
> finally
> strs.Free;
> end;
--
Anders Isaksson, Sweden
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Peter Below (TeamB)
> I have try a few ways to do this but I seem to be comming up with dead ends!
>
> I have a set of strings ['ACELYLENE','ETHANE','ETHYLENE',etc] now I would like test them against a variable that is obtained from another source.
>
> So we can go the route of:
> IF (Comp = 'ACETYLENE') or (Comp = 'ETHANE') or .... then
>
> But is there a better method of checking whether Comp is in the set of parameters?
As Joanne said in her reply putting the strings into a Tstringlist and using
its IndexOf method is one approach. For a set of literal strings you may find this
little routine useful, though:
{: Tests if aString is in the passed array of strings
@Param aString is the string to test for
@Param A is an array of strings to test against
@Param caseSensitive determines whether the test is case-sensitive
or not
@Returns true if aString is one of the strings in the array, false if
not. }
function StringIn(const aString: string;
const A: array of string;
caseSensitive: Boolean = true): Boolean;
var
i: Integer;
begin { StringIn }
Result := false;
for i := Low(A) to High(A) do begin
if caseSensitive then
Result := AnsiCompareStr(aString, A[i]) = 0
else
Result := AnsiCompareText(aString, A[i]) = 0;
if Result then
Break;
end; { For }
end; { StringIn }
Use is like this:
if StringIn(Comp, ['ACELYLENE','ETHANE','ETHYLENE']) then
....
You can also pass a array-of-string constant to this function.
--
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Tom Dalton
Regards
Tom Dalton
Anthony Frazier
> if strs.IndexOf(testStr) > -1 then
> // testStr is in the list
Sorting the list and using the Find method may be better if lots of
lookups need done. Find uses a binary search versus IndexOf's linear
search.
--
Pax tecum,
Anthony Frazier
Victor Printing, Inc.
Anthony Frazier
> As Joanne said in her reply putting the strings into a Tstringlist and using
> its IndexOf method is one approach. For a set of literal strings you may find this
> little routine useful, though:
This looks a lot like AnsiMatchText/AnsiMatchStr, which are available in
Delphi 7 (at least, maybe earlier?). In Delphi 2005 there's now
MatchText/MatchStr. Right now they're only inline calls to the Ansi-
functions, but who knows what they may become in future versions.
There are also AnsiIndexText/AnsiIndexStr if you want the position in
the array. (Good for case statements and the like.)
These should all be in StrUtils.
Wayne Niddery [TeamB]
>
> Sorting the list and using the Find method may be better if lots of
> lookups need done. Find uses a binary search versus IndexOf's linear
> search.
If the Sorted property is true then IndexOf calls Find itself, so no need to
test for which method to call.
--
Wayne Niddery - Logic Fundamentals, Inc. (www.logicfundamentals.com)
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"True peace is not the absence of tension, but the presence of
justice." - Martin Luther King, Jr.
Anthony Frazier
> If the Sorted property is true then IndexOf calls Find itself, so no need to
> test for which method to call.
::Peeks at VCL Source:: Ah! Thanks!