Help with regex
lazarus / 31-LCL

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mebus08 · 2016-12-30 10:30

I have a expression like that : <div
class="titel">(.*?)<\/div>\((.*?)\) <span>(.*?)<\/span>.*?<\/td><\/tr>
to match 1. & 3.

1. <div class="titel">aaa</div>(bbb) <span>ccc</span>xyz</td></tr>
2. <div class="titel">aaa</div><span>xxx</span> (xxx)</td></tr>
3. <div class="titel">aaa</div>(bbb) <span>ccc</span>xyz</td></tr>
4. <div class="titel">aaa</div>(bbb) <span>ccc</span>xyz</td></tr>

but when i list the matches i become

1. aaa bbb ccc  (ok)
2. aaa</div><span>xxx</span> (xxx)</td></tr> (3.bbb) (3.ccc)
3. (4.aaa) (4.bbb) (4.ccc)


what is wrong? can you help me please?

i used the regexpr unit

thanks for help

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Jurassic Pork · 2016-12-30 12:49

hello,
can you put your code in the forum ?
friendly, J.P

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turronet · 2016-12-30 16:00

Hello,

in the second field You are looking for "(" + the content to be
extracted + ") " the second string simply doesn't match because there
aren't any bracket and space

try this regex, it's able to extract all 3 fields

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i <div
class="titel">(.*?)<\/div>[\(]*(.*?)[\)]*[
]*<span>(.*?)<\/span>.*?<\/td><\/tr>
Regards

Valerio

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Jurassic Pork · 2016-12-30 16:02

with this code :
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
implementation uses regexpr;{$R *.lfm}{ TForm1 }procedure
TForm1.Button1Click(Sender: TObject);var i : integer;     Re1:
TRegExpr;begin      try       re1 := TRegExpr.Create;     
 re1.Expression := '<div class="titel">(.*?)<\/div>\((.*?)\)
<span>(.*?)<\/span>.*?<\/td><\/tr>';       for i := 0 to
Memo1.Lines.Count-1 do       begin       if re1.Exec(Memo1.Lines[i])
then  Memo2.Lines.Add( intToStr(i+1) + ' : ' +     
 Trim(Re1.Match[1]) + ' - ' +       Trim(Re1.Match[2]) + ' - ' +     
 Trim(Re1.Match[3]));       end;       finally       re1.Free;     
end;end;
i get this :

Quote1 : aaa - bbb - ccc
3 : aaa - bbb - ccc
4 : aaa - bbb - ccc
line 2 doesn't match the pattern

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Martin_fr · 2016-12-30 20:22

Assuming that line 2 is not supposed to be matched (it does not have
the text between /div and span)...

There is a classic mistake
QuoteCode: [Select](.*?)<\/div>xxxxx\(This is none greedy.
But this does NOT mean "match up to the next "</div>".
It means much up to the next  "</div>", after which the entire rest of
the regex also matches

So in line 2 the  "</div>" is not matched by the "\(" part, and
therefore the regex searches for another  "</div>".

If your text parts to never include any html tags themselves, then
match [^<]*? instead of .*?

Otherwise (if the regex engine has lookahead syntax)
Code: [Select]<div
class="titel">((?:[^<]|(?:<(?!\/div)})*?)<\/div>\((.*?)\)and similar
for other .*?

((?:[^<]|(?:<(?!div)})*?) explained

Quote(              normal ( to catch the matched text
  (?:        begin group (do not catch text / not a result group)
     [^<]    any none <
     |         or
    (?:              group
       <(?!\/div)    match a <, but only if not followed by /div 
 (negative look ahead)
     }                end group
  )*?       end group, and match as often as needed
)

this does not work for nested div.

============
if you have no look ahead then make the rest of the reg ex optional,
and check in your code if it was present
Code: [Select]<div class="titel">(.*?)<\/div>(?:\((.*?)\)
<span>(.*?)<\/span>.*?<\/td><\/tr>)?
Note that after the /div there is a (?:   )?
so the next div can (and will) always be matched, because there is no
requirement after that.

Again repeat the fix for other .*?

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mebus08 · 2016-12-31 09:48

first thanks for the help

the code from  turronet work fine for me.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i <div
class="titel">(.*?)<\/div>[\(]*(.*?)[\)]*[
]*<span>(.*?)<\/span>.*?<\/td><\/tr>
when i used the code from Martin_fr i become a exception
(TRegEx(comp): Unrecognized Modifier (pos40)
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i <div
class="titel">(.*?)<\/div>(?:\((.*?)\)
<span>(.*?)<\/span>.*?<\/td><\/tr>)?
this is the code from me

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var       
                                                                     
                                                                     
               regex : TRegExpr;begin  regex := tregexpr.Create;  try 
  regex.Expression:='<div class="titel">(.*?)<\/div>(?:\((.*?)\)
<span>(.*?)<\/span>.*?<\/td><\/tr>)?';    if regex.Exec(input) then  
...

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LuizAmérico · 2016-12-31 10:26

No lookahead in TRegExpr: http://bugs.freepascal.org/view.php?id=29756

I use http://regexr.com/ to test the regex before writing the code