TRegEx.IsMatch question

[karl Jonson 0]

Hi,

This code not giving the result I'm expecting ?

TRegEx.IsMatch(anyStr, '[A-Za-z0-9]{1,5}')

Ab123 gives true

Ab123456 gives true

 

I expected Ab12345 would give false because input is longer than 5

Why ///Ab123456 is giving true ? I expected result to be false as /// don't match pattern ! 

TIA

 

[David Heffernan 2300]

You didn't specify that the pattern had to exhaust the entire string. Capture the match, look at the match, and see. Use a Web tool to test regex and see the matches. This will help you learn more quickly. 

[Anders Melander 1639]

https://regex101.com/r/1RVJ8h/1

[Stefan Glienke 1905]

https://www.regular-expressions.info/anchors.html

[programmerdelphi2k 235]

thanks to Stefan 

 

uses
  RegularExpressions;

procedure TForm1.Button1Click(Sender: TObject);
var
  RegEx: TRegEx;
begin
  RegEx := TRegEx.Create('(^[\w\d]{1,5}$)'); // RegEx := TRegEx.Create('(^[\w\d]{5,5}$)');
  //
  if RegEx.IsMatch('ab123') then
    ShowMessage('match found')
  else
    ShowMessage('not found');
end;

 

Edited December 23, 2022 by programmerdelphi2k