Regular expressions

The e6 Ingestion Engine scalar functions are based on Apache DataFusion and these docs are derived from the DataFusion function reference.

e6 Ingestion Engine uses a PCRE-like regular expression syntax (minus support for several features including look-around and backreferences).

Function	Description	Example	Result
regexp_like(str, pattern [, flags])	Test if pattern matches	regexp_like('hello123', '[0-9]+')	true
regexp_match(str, pattern [, flags])	Return matches	regexp_match('hello123', '([0-9]+)')	[123]
regexp_replace(str, pattern, repl [, flags])	Replace matches	regexp_replace('hello123', '[0-9]+', 'NUM')	'helloNUM'
position(substr IN str)	Position of substring	position('lo' IN 'hello')	4

regexp_like

Returns true if a regular expression has at least one match in a string, false otherwise.

regexp_like(str, regexp[, flags])

Arguments

• str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• regexp: Regular expression to test against the string expression. Can be a constant, column, or function.
• flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:

  • i: case-insensitive: letters match both upper and lower case
  • m: multi-line mode: ^ and $ match begin/end of line
  • s: allow . to match \n
  • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
  • U: swap the meaning of x* and x*?

Example

select regexp_like('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');
+--------------------------------------------------------+
| regexp_like(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |
+--------------------------------------------------------+
| true                                                   |
+--------------------------------------------------------+
SELECT regexp_like('aBc', '(b|d)', 'i');
+--------------------------------------------------+
| regexp_like(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |
+--------------------------------------------------+
| true                                             |
+--------------------------------------------------+

regexp_match

Returns a list of regular expression matches in a string.

regexp_match(str, regexp[, flags])

Arguments

• str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• regexp: Regular expression to match against. Can be a constant, column, or function.
• flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:

  • i: case-insensitive: letters match both upper and lower case
  • m: multi-line mode: ^ and $ match begin/end of line
  • s: allow . to match \n
  • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
  • U: swap the meaning of x* and x*?

Example

select regexp_match('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');
+---------------------------------------------------------+
| regexp_match(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |
+---------------------------------------------------------+
| [Köln]                                                  |
+---------------------------------------------------------+
SELECT regexp_match('aBc', '(b|d)', 'i');
+---------------------------------------------------+
| regexp_match(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |
+---------------------------------------------------+
| [B]                                               |
+---------------------------------------------------+

regexp_replace

Replaces substrings in a string that match a regular expression.

regexp_replace(str, regexp, replacement[, flags])

Arguments

• str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• regexp: Regular expression to match against. Can be a constant, column, or function.
• replacement: Replacement string expression. Can be a constant, column, or function, and any combination of string operators.
• flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:

  • g: (global) Search globally and don't return after the first match
  • i: case-insensitive: letters match both upper and lower case
  • m: multi-line mode: ^ and $ match begin/end of line
  • s: allow . to match \n
  • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
  • U: swap the meaning of x* and x*?

Example

SELECT regexp_replace('foobarbaz', 'b(..)', 'X\\1Y', 'g');
+------------------------------------------------------------------------+
| regexp_replace(Utf8("foobarbaz"),Utf8("b(..)"),Utf8("X\1Y"),Utf8("g")) |
+------------------------------------------------------------------------+
| fooXarYXazY                                                            |
+------------------------------------------------------------------------+
SELECT regexp_replace('aBc', '(b|d)', 'Ab\\1a', 'i');
+-------------------------------------------------------------------+
| regexp_replace(Utf8("aBc"),Utf8("(b|d)"),Utf8("Ab\1a"),Utf8("i")) |
+-------------------------------------------------------------------+
| aAbBac                                                            |
+-------------------------------------------------------------------+

position

Returns the position of substr in origstr (counting from 1). If substr does not appear in origstr, return 0.

position(substr in origstr)

Arguments

• substr: The pattern string.
• origstr: The model string.