Regular Expression patterns

[Former Member]

Hi,

I need to write patterns for the below examples. Can someone help me.

I need to search for regular expression for..

ZI_SD_yyyy_TOP

(The question is in the above word how can I make sure that the last of the word is 'TOP'. There should not be any more letter after TOP.

ZI_FI_DOCPOST_F01

(In the above one I need to find that the last three letters should be any alphabet followed by two numbers and there should not be any more characters after F01

Thanks,

Sri

[Former Member]

Use this snippet.

IF 'ZI_SD_yyyy_TOP' CP 'ZI_SD*TOP'.
  WRITE:/ 'found'.
ENDIF.
IF 'ZI_FI_DOCPOST_F01' CP 'ZI_FI*F01'.
  WRITE:/ 'found'.
ENDIF.

[Former Member]

So to get the F01 right:

Get the length of the string

Pos1 = length -3

Pos2 = length -2

String+Pos1(1) CN (0123456789)

String+Pos2(2) CO (0123456789)

This is pseudo code, of course.

Neal

[matt]

That's not a Regular Expression.

[Former Member]

Yes that was just a pattern.

[naimesh_patel]

To find the end of the String, you need to use the end of the string indicator $.

To find TOP at last, use TOP$

To find F01 or as a matter of fact the fist character followed by numbers, use

[A-Z][0-9][0-9]$

Something like this:

 DATA: lv_input TYPE string.
 DATA: result_tab TYPE match_result_tab.
 DATA: mcnt TYPE i.
 * positive
 lv_input = 'ZI_SD_yyyy_TOP'.
 FIND FIRST OCCURRENCE OF REGEX 'TOP$'
   IN lv_input
   MATCH COUNT  mcnt
   RESULTS result_tab.
 WRITE: /(20) lv_input, (15)mcnt.
 * negative
 lv_input = 'ZI_SD_yyyy_TOP_1'.
 FIND FIRST OCCURRENCE OF REGEX 'TOP$'
   IN lv_input
   MATCH COUNT  mcnt
   RESULTS result_tab.
 WRITE: /(20) lv_input, (15)mcnt.
 * Positive
 lv_input = 'ZI_FI_DOCPOST_F01'.
 FIND FIRST OCCURRENCE OF REGEX '[A-Z][0-9][0-9]$'
   IN lv_input
   MATCH COUNT  mcnt
   RESULTS result_tab.
 WRITE: /(20) lv_input, (15)mcnt.
 *negative
 lv_input = 'ZI_FI_DOCPOST_F01_1'.
 FIND FIRST OCCURRENCE OF REGEX '[A-Z][0-9][0-9]$'
   IN lv_input
   MATCH COUNT  mcnt
   RESULTS result_tab.
 WRITE: /(20) lv_input, (15)mcnt.

Thanks,
Naimesh Patel

[matt]

Ah good. Someone who knows what a Regular Expression is.

[Former Member]

Those who played with the REGEX_TOY should know what it is

[naimesh_patel]

Correct program would be DEMO_REGEX_TOY

[Former Member]

Forget that, DEMO and TOY are just for Playing

[SuhaSaha]

Good to see you @SCN ...

RegEx has been around for quite sometime but ABAPers are still fixated on CP, NP et al. Imho they are more elegant (and sometimes even more complex ) to use than the ABAP string operators.

Honestly I tend to use simple RegEx and avoid using complex ones

Cheers,

Suhas

[Former Member]

Hi Naimesh,

That was really a helpful answer, But I'm looking for more patterns here. Can we check the length of string using these regular expressions. Suppose I have "ZBH_XX'   where XX is module name say SD.

ZBH is always constant and I should only use two characters in place of XX. So totally need to check thru regular expression if the string is of length 6 and at the same time checking if ZBH_ are the first four characters and then followed by two characters only ( total length is 6 characters).

I tried using "ZBH[_][A-Z]{2} but failed to get correct entries . using FIND FIRST OCCURENCE OF regex is also showing "ZBH_ABC' also as correct answer.

I will be waiting for your answer.

Thanks,

Sri

[Former Member]

Use this regex and see how value of sy-subrc changes.

FIND REGEX '^ZBH_[A-Z]{2}$' IN 'ZBH_XXABC'.
WRITE:/ sy-subrc.
FIND REGEX '^ZBH_[A-Z]{2}$' IN 'ZBH_XX'.
WRITE:/ sy-subrc.

Message was edited by: Manish Kumar

[naimesh_patel]

What you need is the $ sign at end of the regex to tell the regex to stop searching after 2 characters {2}.

So, your regex would be ZBH_[A-Z]{2}$

Use program DEMO_REGEX_TOY to test it out.

Input:

ZBH_SD

ZBH_SD_1

ZBH_ABC

ZBH_AB

Select ALL Occurnaces

Output (highlighted are match):

ZBH_SD
ZBH_SD_1
ZBH_ABC
ZBH_AB

BTW, you didn't mention this in your earlier question so don't expect to get answer. You need to ask to get the direction!

sri r wrote:
Hi Naimesh,
That was really a helpful answer, But I'm looking for more patterns here. Can we check the length of string using these regular expressions. 

Thanks,

Naimesh Patel

[naimesh_patel]

Hello Suhas - Glad that you noticed Just kidding.

I try to use Regex for every possible opportunity. I need to admit, that I might not get that many chances. To your point, I know many developers don't yet realize the power of regex thus dont care to use it.

Regards,
Naimesh Patel

[Former Member]

Hi Naimesh,

Thanks for the information you provided which was helpful. You are right, I should have added the second question earlier in the discussion but I realized it later. Anyways this question is now answered.