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--- cheat_sheets_regex [2022/09/25 14:27] – [RegEx] gman
+++ cheat_sheets_regex [2023/02/11 14:34] (current) – [Groups and Ranges] gman
@@ Line 48: / Line 48: @@
 |  [A-Q]       | Upper case letter from A to Q      |
 |  [0-7]       | Digit from 0 to 7                  |
+Use a group to "capture and replace".
+  * ''a(bc)'' parentheses create a capturing group with value ''bc''
+  * The parentheses are used to create "groups," which then get assigned a base-1 index, accessible in a //replace// with a ''$'' (i.e., the first parentheses-bounded (characters) become a group that can be referenced by ''$1'', the second group would be ''$2'', the third ''$3'', etc.).
+  * NOTE: in **gedit** you reference with a backslash: ''\'' not a ''$'' (i.e., ''\1\2\3'', etc.).
+  * See the follow table regarding **string replacements**.
 ----
@@ Line 53: / Line 59: @@
 ===== String Replacement =====
-^  Syntax      ^ Description                        ^
+^  Syntax      ^ Description           ^
-|  $n  | nth non-passive group |
+|  $n  | nth non-passive group         |
-|  $2  | "xyz" in /^(abc(xyz))$/ |
+|  $2  | %%"xyz" in /^(abc(xyz))$/%%   |
-|  $1  | "xyz" in /^(?:abc)(xyz)$/ |
+|  $1  | %%"xyz" in /^(?:abc)(xyz)$/%% |
-|  $`  | Before matched string |
+|  $`  | Before matched string         |
-|  $'  | After matched string |
+|  $'  | After matched string          |
-|  $+  | Last matched string |
+|  $+  | Last matched string           |
-|  $&  | Entire matched string |
+|  $&  | Entire matched string         |
 **Note:** Some regex implementations use \ instead of $.
@@ Line 68: / Line 74: @@
 ===== Character Classes =====
-^  Syntax  ^ Description                        ^
+^  Syntax  ^ Description   ^
 |  \c  | Control character |
-|  \s  | White space |
+|  \s  | White space       |
-|  \S  | Not white space |
+|  \S  | Not white space   |
-|  \d  | Digit |
+|  \d  | Digit             |
-|  \D  | Not digit |
+|  \D  | Not digit         |
-|  \w  | Word |
+|  \w  | Word              |
-|  \W  | Not word |
+|  \W  | Not word          |
 |  \x  | Hexadecimal digit |
-|  \O  | Octal digit |
+|  \O  | Octal digit       |
 ----
@@ Line 83: / Line 89: @@
 ===== POSIX =====
-^  Syntax      ^ Description                        ^
+^  Syntax      ^ Description                    ^
-|  [:upper:]  | Upper case letters
+|  [:upper:]   | Upper case letters             |
-|  [:lower:]  | Lower case letters
+|  [:lower:]   | Lower case letters             |
-|  [:alpha:]  | All letters
+|  [:alpha:]   | All letters                    |
-|  [:alnum:]  | Digits and letters
+|  [:alnum:]   | Digits and letters             |
-|  [:digit:]  | Digits
+|  [:digit:]   | Digits                         |
-|  [:xdigit:]  | Hexadecimal digits
+|  [:xdigit:]  | Hexadecimal digits             |
-|  [:punct:]  | Punctuation
+|  [:punct:]   | Punctuation                    |
-|  [:blank:]  | Space and tab
+|  [:blank:]   | Space and tab                  |
-|  [:space:]  | Blank characters
+|  [:space:]   | Blank characters               |
-|  [:cntrl:]  | Control characters
+|  [:cntrl:]   | Control characters             |
-|  [:graph:]  | Printed characters
+|  [:graph:]   | Printed characters             |
-|  [:print:]  | Printed characters and spaces
+|  [:print:]   | Printed characters and spaces  |
-|  [:word:]  | Digits, letters and underscore
+|  [:word:]    | Digits, letters and underscore |
+----
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