ABAP Keyword Documentation → ABAP - Reference → Processing Internal Data → Character String and Byte String Processing → Expressions and Functions for String Processing → Regular Expressions → Syntax of Regular Expressions
Special Characters in Regular Expressions
The following tables summarize the special characters in regular expressions:
Other versions: 7.31 | 7.40 | 7.54
Escape Character
| Special character | Meaning |
|---|---|
| \ | Escape character for special characters |
Note
With the escape character string, all special characters for regular expressions can come before their escape characters.
Special Characters for Single Character Strings
| Special character | Meaning |
|---|---|
| . | Placeholder for any single character |
| \C | Placeholder for any single character |
| \d | Placeholder for any single digit |
| \D | Placeholder for any character other than a digit |
| \l | Placeholder for any lowercase letter |
| \L | Placeholder for any character other than a lowercase letter |
| \s | Placeholder for a blank character |
| \S | Placeholder for any character other than a blank character |
| \u | Placeholder for any uppercase letter |
| \U | Placeholder for any character other than an uppercase letter |
| \w | Placeholder for any alphanumeric character including _ |
| \W | Placeholder for any non-alphanumeric character except for _ |
| [ ] | Definition of a value set for single characters |
| [^ ] | Negation of a value set for single characters |
| [ - ] | Definition of a range in a value set for single characters |
| [[:alnum:]] | Description of all alphanumeric characters in a value set |
| [[:alpha:]] | Description of all letters in a value set |
| [[:blank:]] | Description for blank characters and horizontal tabulators in a value set |
| [[:cntrl:]] | Description of all control characters in a value set |
| [[:digit:]] | Description of all digits in a value set |
| [[:graph:]] | Description of all characters in a value set that can be displayed apart from blank characters and horizontal tabulators |
| [[:lower:]] | Description of all lowercase letters in a value set |
| [[:print:]] | Description of all characters in a value set that can be displayed |
| [[:punct:]] | Description of all punctuation characters in a value set |
| [[:space:]] | Description of all blank characters, tabulators, and carriage feeds in a value set |
| [[:unicode:]] | Description of all Unicode characters in a value set with a code larger than 255 |
| [[:upper:]] | Description of all uppercase letters in a value set |
| [[:word:]] | Description of all alphanumeric characters in a value set, including _ |
| [[:xdigit:]] | Description of all hexadecimal digits in a value set |
| \a \f \n \r \t \v | Various platform-specific control characters |
| [..] | Reserved for later enhancements |
| [==] | Reserved for later enhancements |
Special Characters for Character String Patterns
| Special character | Meaning |
|---|---|
| Concatenation of n single characters | |
| Concatenation of at least n and a maximum of m single characters | |
| Reserved for later enhancements | |
| ? | One or no single characters |
| * | Concatenation of any number of single characters including 'no characters' |
| *? | Reserved for later enhancements |
| + | Concatenation of any number of single characters excluding 'no characters' |
| +? | Reserved for later enhancements |
| ( ) | Definition of subgroups with registration |
| (?: ) | Definition of subgroups without registration |
| \1, \2, \3 ... | Placeholder for the register of subgroups |
| \Q ... \E | Definition of a string of literal characters |
| (? ... ) | Reserved for later enhancements |
Special Characters for Search Strings
| Special character | Meaning |
|---|---|
| ^ | Anchor character for the start of a line |
| \A | Anchor character for the start of a character string |
| $ | Anchor character for the end of a line |
| \z | Anchor character for the end of a character string |
| \Z | Like \z, whereby line breaks at the end of the character string are ignored |
| \< | Start of a word |
| \> | End of a word |
| \b | Start or end of a word |
| \B | Space between characters within a word |
| (?= ) | Preview condition |
| (?! ) | Negated preview condition |
| (?> ) | Cut operator |
Special Characters for Replacement Texts
| Special character | Meaning |
|---|---|
| $0, $& | Placeholder for the whole found location |
| $1, $2, $3... | Placeholder for the register of subgroups |
| $` | Placeholder for the text before the found location |
| $' | Placeholder for the text after the found location |