Lazarus

Free Pascal => Beginners => Topic started by: JLWest on March 20, 2019, 01:50:20 am

Title: ExtractWordPos ?
Post by: JLWest on March 20, 2019, 01:50:20 am

function ExtractWordPos( N: Integer;
                                     const S: string;
                                    const WordDelims: TSysCharSet;
                                   var Pos: Integer) : string;

I think I would like to use this function but not sure how to call it.

Var
 Answer : String;
 aPos      : Integer;
 Item      : String = 'Now is the time for all good men';

begin
Answer := ExtractWordPos(4,Item,['  '] , aPos);

And wouldb't it return 4 because I specifying 4 in  "N: Integer";

It's obvious that I'm not reading this right;

Title: Re: ExtractWordPos ?
Post by: lucamar on March 20, 2019, 02:11:45 am

The function returns the Nth word as result and the character position in which it was found in Pos

With your example it should return "time" and "aPos = 12". Does it return something else?

Title: Re: ExtractWordPos ?
Post by: BobDog on March 20, 2019, 02:51:13 am

According to the help file
. . .
function ExtractWordPos(
  N: Integer;
  const S: string;
  const WordDelims: TSysCharSet;
  out Pos: Integer
):string;


N   Which word to extract
S    String to extract a word from.
WordDelims  Characters to use as word delimiters
Pos    On return, contains the position of the N-th word.
. . .
But if I make the deliminator more than one character I get an error.
So, just one space as deliminator.

Code: Pascal  [Select][+][-]

1.    
2.  
3. program pos;
4. uses strutils;
5.  
6.  
7. Var
8.  Answer : String;
9.  aPos      : Integer;
10.  Item      : String = 'Now is the time for all good men';
11.  
12. begin
13. Answer := ExtractWordPos(4,Item,[' '] , aPos);
14. writeln(answer,'  ',apos);
15. writeln('Press return to end . . .');
16.  
17. readln;
18. end.

result
time  12
Press return to end . . .
   

 
   

Title: Re: ExtractWordPos ?
Post by: lucamar on March 20, 2019, 04:10:40 am

Quote from: BobDog on March 20, 2019, 02:51:13 am

But if I make the deliminator more than one character I get an error.
So, just one space as deliminator.

WordDelims is a TSysCharSet, i.e. a set of AnsiChar; which means you can use, say:

Code: [Select]

FoundWord := ExtractWordPos(N, SrcStr, [' ', ',', '.', ':', ';'], APos);but, of course, not something like:

Code: [Select]

FoundWord := ExtractWordPos(N, SrcStr, [':::', '=='], APos);

Title: Re: ExtractWordPos ?
Post by: JLWest on March 20, 2019, 04:38:55 am

Thank you;