RegEx pattern not working

[Melba23]

Hi all,

I am trying to develop a RegEx pattern that allows the following:

• One or two digits, possibly followed by a single uppercase letter, possibly followed by * but only if there is a preceding letter.

I have the following effort:

^\d{1,2}[A-Z]?(?<=[A-Z])\*?$

which seems to cope with the more complex cases, but fails if there are only digits. Both the letter and * are quantified as "0 or 1", so I cannot see why the "digit-only" case fails.

My thanks in advance to any guru able to explain why and offer me a working pattern.

M23

[ripdad]

not a guru - but this might work...

(\d{1,2}[A-Z]\*?|\d{1,2}[A-Z]?)

 

[Bowmore]

If I have interpreted your requirements correctly this '^\d{1,2}([A-Z][*]?)?$' works

$res = StringRegExp('12','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('1A','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('12A*','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('12AB','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('12AB*','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('1AB*','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('1*','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

$res = StringRegExp('12*','^\d{1,2}([A-Z][*]?)?$')
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $res = ' & $res & @CRLF & '>Error code: ' & @error & @CRLF) ;### Debug Console

 

[mikell]

Melba 

$str = "12"

$res = StringRegExp($str, '^\d{1,2}[A-Z]?(?<=[A-Z])\*?$' )
Msgbox(0,"", $res)

$res = StringRegExp($str, '^\d{1,2}[A-Z]?((?<=[A-Z])\*)?$' )
Msgbox(0,"", $res)


;   ^\d{1,2}([A-Z]\*?)?$

 

Edited January 29, 2017 by mikell

[Melba23]

Thanks to all responders.

M23

[jguinch]

Using a conditional pattern :

$res = StringRegExp($str, '^\d\d?([A-Z])?(?(1)\*?)$')

or just a Or operator :

$res = StringRegExp($str, '^\d\d?([A-Z]?|[A-Z]\*?)$')

 

Edited January 29, 2017 by jguinch

[Melba23]

jguinch,

Thanks for that - I have never used conditional matches before, so a very educational example.

Damn RegExes still make my brain bleed!

M23