Regular Expression in ABAP

[Former Member]

In an Upload file (Excel sheet ) I had a requirement to validate the amount ( currency ). Below were the validations to be considered for the string containing the amount

1. The string must contains numbers and decimal dot only(optional decimal).
2. There must be only 13 digits before decimal and 2 digits after decimal.
3. There should not be any special characters in the string apart from decimal point.
4. Only one decimal point should be used in the string.

To achieve this initially, I used the below logic on the sting <amount>.

1. <amount> contains only (1234567890.)

1. Separate the <amount> into <first_part> <second_part> <third_part> at '.'

   Find the length of <first_part>.

   Find the length of <second_part>.

   Check <first_part> < 13 and <second_part> < 2.

   Check <third_part> is initial.

1. <amount> is less than 0.

This all validation takes nearly around 25 - 30 lines of code.

But, after knowing the Regular expression concept I revised this 25 - 30 lines of code into just 1 line as below.

FIND ALL OCCURRENCES OF regex '^([0-9]\d{0,12})(\.[0-9]{0,2})?$' IN <amount> MATCH COUNT sy-tabix.

sy-tabix = 1 => its true/correct.

sy-tabix = 0 => its wrong/ incorrect.

Brief Explanation.

Syntax : FIND ALL OCCURRENCES OF regex <Expression> in <String> Match Count <Variable> .

Regular Expression : ^([0-9]\d{0,12})(\.[0-9]{0,2})?$

^ : Matches the starting position within the string

() : The string matched within the parentheses can be recalled later.

[] : Matches a character that is contained within the brackets.

- : Specifies a range.

{} : Number of characters.

\d : Digits.

\. : Mandatory dot.

?  : Indicates there is zero or one of the preceding element.

$ : Matches the ending position of the string.

[0-9]       : Digits only any number between 0 to 9.

{0,12}     : Up to 13 characters allowed only before decimal.

{0,2}        : up to 2 characters allowed only after decimal.

Regards

Rounak