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cheat_sheets_regex [2022/09/25 14:09] – gmancheat_sheets_regex [2023/02/11 14:34] (current) – [Groups and Ranges] gman
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 [[https://cheatography.com/davechild/cheat-sheets/regular-expressions/|Good Cheat Sheet]] | [[https://medium.com/factory-mind/regex-tutorial-a-simple-cheatsheet-by-examples-649dc1c3f285|Basic Explanation]] [[https://cheatography.com/davechild/cheat-sheets/regular-expressions/|Good Cheat Sheet]] | [[https://medium.com/factory-mind/regex-tutorial-a-simple-cheatsheet-by-examples-649dc1c3f285|Basic Explanation]]
  
----- 
  
 ===== Anchors ===== ===== Anchors =====
  
- +^  Syntax  ^ Description                                             ^
-^  Syntax  ^ Description ^+
 |  %%^%%   | Start of string, or start of line in multi-line pattern | |  %%^%%   | Start of string, or start of line in multi-line pattern |
 |  $       | End of string, or end of line in multi-line pattern     | |  $       | End of string, or end of line in multi-line pattern     |
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 ===== Quantifiers ===== ===== Quantifiers =====
  
-^ Syntax ^ Description ^+^  Syntax    ^ Description                                 ^
 |  *         | 0 or more                                   | |  *         | 0 or more                                   |
 |  ?         | 0 or 1                                      | |  ?         | 0 or 1                                      |
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 ===== Escape ===== ===== Escape =====
  
- +^  Syntax  ^ Description                ^ 
-^ Syntax ^ Description ^ +|  \       | Escape following character |
-|  \  | Escape following character |+
  
 **//­Esc­api­ng//** is a way of treating characters which have a special meaning in regular expres­sions literally, rather than as special charac­ters. **//­Esc­api­ng//** is a way of treating characters which have a special meaning in regular expres­sions literally, rather than as special charac­ters.
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 ===== Groups and Ranges ===== ===== Groups and Ranges =====
  
-^ Syntax ^ Description ^ +^  Syntax      ^ Description                        ^ 
-|  .       | Any character except new line (\n) | +|  .           | Any character except new line (\n) | 
-|  (a|b)   | a or b                             | +|  (a%%|%%b)   | a or b                             | 
-|  (...)   | Group, capturing                   | +|  (...)       | Group, capturing                   | 
-|  (?:...) | Passive (non-c­apt­uring) group      |  +|  (?:...)     | Passive (non-c­apt­uring) group      |  
-|  [abc]   | Range (a or b or c)                | +|  [abc]       | Range (a or b or c)                | 
-|  [^abc]  | Not (a or b or c)                  |  +|  [%%^%%abc]  | Not (a or b or c)                  |  
-|  [a-q]   | Lower case letter from a to q      | +|  [a-q]       | Lower case letter from a to q      | 
-|  [A-Q]   | Upper case letter from A to Q      |  +|  [A-Q]       | Upper case letter from A to Q      |  
-|  [0-7]   | Digit from 0 to 7                  |+|  [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**. 
 + 
 +---- 
 + 
 +===== String Replac­ement ===== 
 + 
 +^  Syntax      ^ Description           ^ 
 +|  $n  | nth non-pa­ssive group         | 
 +|  $2  | %%"­xyz­" in /^(abc­(xy­z))$/%%   | 
 +|  $1  | %%"­xyz­" in /^(?:a­bc)­(xyz)$/%% | 
 +|  $`  | Before matched string         | 
 +|  $'  | After matched string          | 
 +|  $+  | Last matched string           | 
 +|  $&  | Entire matched string         | 
 + 
 +**Note:** Some regex implem­ent­ations use \ instead of $. 
 + 
 +---- 
 + 
 +===== Character Classes ===== 
 + 
 +^  Syntax  ^ Description   ^ 
 +|  \c  | Control character | 
 +|  \s  | White space       | 
 +|  \S  | Not white space   | 
 +|  \d  | Digit             | 
 +|  \D  | Not digit         | 
 +|  \w  | Word              | 
 +|  \W  | Not word          | 
 +|  \x  | Hexade­cimal digit | 
 +|  \O  | Octal digit       | 
 + 
 +---- 
 + 
 +===== POSIX ===== 
 + 
 +^  Syntax      ^ Description                    ^ 
 +|  [:upper:]   | Upper case letters             | 
 +|  [:lower:]   | Lower case letters             | 
 +|  [:alpha:]   | All letters                    | 
 +|  [:alnum:]   | Digits and letters             | 
 +|  [:digit:]   | Digits                         | 
 +|  [:xdigit:]  | Hexade­cimal digits             | 
 +|  [:punct:]   | Punctu­ation                    | 
 +|  [:blank:]   | Space and tab                  | 
 +|  [:space:]   | Blank characters               | 
 +|  [:cntrl:]   | Control characters             | 
 +|  [:graph:]   | Printed characters             | 
 +|  [:print:]   | Printed characters and spaces  | 
 +|  [:word:]    | Digits, letters and underscore |
  
 ---- ----
  
cheat_sheets_regex.1664114981.txt.gz · Last modified: by gman