Number of input and output field

Number of input field	:	One
Number of output field	:	One

This transformation function is used to replace a portion of the input text with another text based on a regular expression matching pattern.
The parameters of this function are:

• Pattern Expression
  The regular expression pattern that identifies the text to be replaced.
• Target Text
  The text to be replaced. If omitted, the text matched by the pattern expression is replaced with the replacement text.
• Replacement Text
  The text used as the replacement.
• Pattern - flag
  Indicates the regular expression flags (multiple flags are separated by |).

Here below are the tables used in Regular Expressions:

Table 1 : Character representations

Sequence	Meaning
\a	Alert (bell).
\b	Backspace, \x08, supported only in character class.
\e	Esc character, \x1B.
\n	Newline, \x0A.
\r	Carriage return, \x0D.
\f	Form feed, \x0C.
\t	Horizontal tab, \x09.
\0octal	Character specified by a one-, two-, or three-digit octal
\xhex	Character specified by a two-digit hexadecimal code.
\uhex	Unicode character specified by a four-digit hexadecimal code.
\cchar	Named control character.

Table 2 : Character classes and class-like constructs .

Class	Meaning
[...]	A single character listed or contained in a listed range.
[^...]	A single character not liste and not contained within a listed range.
.	Any character, except a line terminator (unless DOTALL mode).
\w	Word character,[a-zA-Z0-9_].
\W	Nonword character,[^a-zA-Z0-9_].
\d	Digit,[0-9].
\D	Nondigit,[^0-9].
\s	Whitespace character,[ \t\n\f\r\x0B].
\S	Nonwhitespace character,[^ \t\n\f\r\x0B].
\p{prop}	Character contained by given POSIX character class, Unicode property, or Unicode block.
\P{prop}	Character not contained by given POSIX character class,Unicode property, or Unicode block.

Table 3 : Anchors and other zero-width tests.

Sequence	Meaning
^	Start of string, or the point after any newline if in MULTILINE mode.
\A	Beginning of string, in any match mode.
$	End of string, or the point before any newline if in MULTILINE mode.
\Z	End of string, but before any final line terminator, in any match mode.
\z	End of string, in any match mode.
\b	Word boundary.
\B	Not-word-boundary.
\G	Beginning of current search.
(?=...)	Positive lookahead.
(?!...)	Negative lookahead.
(?<=...)	Positive lookbehind.
(?	Negative lookbehind.

Table 4 : Comments and mode modifiers.

Modifier/sequence	Mode character	Meaning
Pattern.DOTALL	s	Dot (.) matches any character, including a line terminator.
Pattern.MULTILINE	m	^ and $ match next to embedded line terminators.
Pattern.COMMENTS	x	Ignore whitespace, and allow embedded comments starting with #.
Pattern.CASE_INSENSITIVE	i	Case-insensitive match for ASCII characters.
Pattern.UNICODE_CASE	u	Case-insensitive match for Unicode characters.
Pattern.CANON_EQ		Unicode 'canonical equivalence' mode, where characters, or sequences of a base character and combining characters with identical visual representations, are treated as equals.
(?mode)		Turn listed modes(one or more of idmsux) on for the rest of the subexpression.
(?-mode)		Turn listed modes(one or more of idmsux) off for the rest of the subexpression.
(?mode:...)		Turn listed modes(one or more of idmsux) on within parentheses.
(?-mode:...)		Turn listed modes(one or more of idmsux) off within parentheses.
#...		Treat rest of line as a comment in /xmode

Table 5 : Grouping, capturing, conditional,and control.

Sequence	Meaning
(...)	Group subpattern and capture submatch into\1,\2,...and $1,$2,....
\n	Contains text matched by thenth capture group. $n In a replacement string, contains text matched by the nth capture group.
(?:...)	Groups subpattern, but does not capture submatch.
(?>...)	Atomic grouping.
...|...	Try subpatterns in alternation.
*	Match 0 or more times.
+	Match 1 or more times.
?	Match 1 or 0 times.
{n}	Match exactlyntimes.
{n,}	Match at leastntimes.
{x,y}	Match at leastxtimes, but no more thanytimes.
*?	Match 0 or more times, but as few times as possible.
+?	Match 1 or more times, but as few times as possible.
??	Match 0 or 1 times, but as few times as possible.
{n,}?	Match at leastntimes, but as few times as possible.
{x,y}?	Match at leastxtimes, no more thanytimes, and as few times as possible.
*+	Match 0 or more times, and never backtrack.
++	Match 1 or more times, and never backtrack.
?+	Match 0 or 1 times, and never backtrack.
{n}+	Match at leastntimes, and never backtrack.
{n,}+	Match at leastntimes, and never backtrack.
{x,y}+	Match at leastxtimes, no more thanytimes, and never backtrack

Notes:
\ is used as for escape sequence in many programming languages, including Java.
Printing a \ or " which are special in string literal you have to escape it with another \ which gives us \\ and \"