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![SPECIAL CHARACTERS
4
Metacharacter Description
* Zero or more
+ One or more
? Zero or one; Not greedy
^ Beginning of string
$ End of string
. Any
[] Group
{} Marks the start and end of a quantifier expression
() Capture
| or
Escape](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-4-320.jpg)
![METACHARACTERS
5
Metacharacter Description
b Word boundary
B Non word boundary
d Decimal digit
Equivalent to [0-9]
D Non decimal digit
Equivalent to [^0-9]
w Word
Equivalent to [a-zA-Z_0-9]
W Non word
Equivalent to [^a-zA-Z_0-9]
[xyz] Group
[^xyz] Negated group
[a-z] Group](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-5-320.jpg)
![METACHARACTERS
6
Metacharacter Description
[^a-z] Negated group
{n} Exactly N
{n,} At least N
{n,m} From N to M
(pattern) Capture
(?<name>pattern) Named capture
(?:pattern) Non capture
(?=pattern) Positive lookahead
(?!pattern) Negative lookahead
(?<=pattern) Positive lookbehind
(?<!pattern) Negative lookbehind
cx CTRL char
xn ASCII value](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-6-320.jpg)
![NONPRINTING CHARACTERS
7
Metacharacter Description
f Form feed
Equivalent to x0ccL
n New line
Equivalent to x0acJ
r Carriage return
Equivalent to x0dcM
s Whitespace
Equivalent to [fnrtv]
S Non whitespace
Equivalent to [^fnrtv]
t Tab
Equivalent to x09cI
v Vertical tab
Equivalent to x0bcK](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-7-320.jpg)
![ORDER OF PRECEDENCE
8
Operator or operators Description
Escape
(), (?:), (?=), [] Parentheses and brackets
*, +, ?, {n}, {n,}, {n,m} Quantifiers
^, $, anymetacharacter Anchors and sequences
| Alternation](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-8-320.jpg)
![EXAMPLE
Digits
^[0-9]*$
Alphabetic characters
^[a-zA-Z]*$
Alpha-Numeric characters
^[a-zA-Z0-9]*$
Special characters
[W_]+ 10](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-10-320.jpg)
![EXAMPLE
Lowercase alphabetic characters
^([a-z])*$
Uppercase alphabetic characters
^([A-Z])*$
11](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-11-320.jpg)
![EXAMPLE
Email
^([a-zA-Z0-9._%-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,4})*$
IP
^(?:(?:25[0-5]|2[0-4]d|[01]dd|d?d)(?(?=.?d).)){4}$
Url
^(((http|https|ftp)://)?([[a-zA-Z0-9]-.])+(.)([[a-zA-Z0-
9]]){2,4}([[a-zA-Z0-9]/+=%&_.~?-]*))*$
12](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-12-320.jpg)
![EXAMPLE
Date (MM/DD/YYYY)
^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[-
/.](19|20)?[0-9]{2})*$
Date (YYYY/MM/DD)
^((19|20)?[0-9]{2}[- /.](0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-
9]|3[01]))*$
Time
([0-1][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]
13](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-13-320.jpg)
![EXAMPLE
Tel
[0-9]{2}-[0-9]{7}
Mobile
[0-9]{4}-[0-9]{3}-[0-9]{3}
ID No
([A-Z]|[a-z])d{9}
HTML element
^<([a-z]+)([^<]+)*(?:>(.*)</1>|s+/>)$ 14](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-14-320.jpg)
![EXAMPLE
Strong password
^(?=^.{6,}$)((?=.*[A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z]))^.*$
Credit card
^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6011[0-
9]{12}|622((12[6-9]|1[3-9][0-9])|([2-8][0-9][0-9])|(9(([0-
1][0-9])|(2[0-5]))))[0-9]{10}|64[4-9][0-9]{13}|65[0-
9]{14}|3(?:0[0-5]|[68][0-9])[0-9]{11}|3[47][0-9]{13})*$
MasterCard credit card
^(5[1-5][0-9]{14})*$
15](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-15-320.jpg)
![EXAMPLE
Zip code
^([0-9]{5}(?:-[0-9]{4})?)*$
16](https://image.slidesharecdn.com/regularexpression-160616044025/85/Regular-expression-16-320.jpg)
Uploaded byLarry Nung
Regular expression
This document provides an introduction to regular expressions including syntax, special characters, metacharacters, order of precedence, examples, and references. It begins with an agenda and overview of syntax. It then defines special characters and metacharacters used in regular expressions. Examples are given for common patterns like digits, email addresses, and credit cards. References for further reading on regular expressions are also included. The document concludes with contact information for questions.
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Regular expression
- 1.
- 2.
- 3.
- 4. SPECIAL CHARACTERS 4 Metacharacter Description *Zero or more + One or more ? Zero or one; Not greedy ^ Beginning of string $ End of string . Any [] Group {} Marks the start and end of a quantifier expression () Capture | or Escape
- 5. METACHARACTERS 5 Metacharacter Description b Wordboundary B Non word boundary d Decimal digit Equivalent to [0-9] D Non decimal digit Equivalent to [^0-9] w Word Equivalent to [a-zA-Z_0-9] W Non word Equivalent to [^a-zA-Z_0-9] [xyz] Group [^xyz] Negated group [a-z] Group
- 6. METACHARACTERS 6 Metacharacter Description [^a-z] Negatedgroup {n} Exactly N {n,} At least N {n,m} From N to M (pattern) Capture (?<name>pattern) Named capture (?:pattern) Non capture (?=pattern) Positive lookahead (?!pattern) Negative lookahead (?<=pattern) Positive lookbehind (?<!pattern) Negative lookbehind cx CTRL char xn ASCII value
- 7. NONPRINTING CHARACTERS 7 Metacharacter Description fForm feed Equivalent to x0ccL n New line Equivalent to x0acJ r Carriage return Equivalent to x0dcM s Whitespace Equivalent to [fnrtv] S Non whitespace Equivalent to [^fnrtv] t Tab Equivalent to x09cI v Vertical tab Equivalent to x0bcK
- 8. ORDER OF PRECEDENCE 8 Operatoror operators Description Escape (), (?:), (?=), [] Parentheses and brackets *, +, ?, {n}, {n,}, {n,m} Quantifiers ^, $, anymetacharacter Anchors and sequences | Alternation
- 9.
- 10. EXAMPLE Digits ^[0-9]*$ Alphabetic characters ^[a-zA-Z]*$ Alpha-Numeric characters ^[a-zA-Z0-9]*$ Special characters [W_]+ 10
- 11. EXAMPLE Lowercase alphabeticcharacters ^([a-z])*$ Uppercase alphabetic characters ^([A-Z])*$ 11
- 12. EXAMPLE Email ^([a-zA-Z0-9._%-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,4})*$ IP ^(?:(?:25[0-5]|2[0-4]d|[01]dd|d?d)(?(?=.?d).)){4}$ Url ^(((http|https|ftp)://)?([[a-zA-Z0-9]-.])+(.)([[a-zA-Z0- 9]]){2,4}([[a-zA-Z0-9]/+=%&_.~?-]*))*$ 12
- 13. EXAMPLE Date (MM/DD/YYYY) ^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)?[0-9]{2})*$ Date (YYYY/MM/DD) ^((19|20)?[0-9]{2}[- /.](0?[1-9]|1[012])[- /.](0?[1-9]|[12][0- 9]|3[01]))*$ Time ([0-1][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9] 13
- 14. EXAMPLE Tel [0-9]{2}-[0-9]{7} Mobile [0-9]{4}-[0-9]{3}-[0-9]{3} ID No ([A-Z]|[a-z])d{9} HTML element ^<([a-z]+)([^<]+)*(?:>(.*)</1>|s+/>)$ 14
- 15. EXAMPLE Strong password ^(?=^.{6,}$)((?=.*[A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z]))^.*$ Credit card ^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6011[0- 9]{12}|622((12[6-9]|1[3-9][0-9])|([2-8][0-9][0-9])|(9(([0- 1][0-9])|(2[0-5]))))[0-9]{10}|64[4-9][0-9]{13}|65[0- 9]{14}|3(?:0[0-5]|[68][0-9])[0-9]{11}|3[47][0-9]{13})*$ MasterCard credit card ^(5[1-5][0-9]{14})*$ 15
- 16. EXAMPLE Zip code ^([0-9]{5}(?:-[0-9]{4})?)*$ 16
- 17.
- 18. REFERENCE 正規表示式 -維基百科，自由的百科全書 https://zh.wikipedia.org/wiki/%E6%AD%A3%E5%88%9 9%E8%A1%A8%E8%BE%BE%E5%BC%8F 正則表達式30分鐘入門教程 http://deerchao.net/tutorials/regex/regex.htm 正規化表示法 - ProgWiki http://www.player.idv.tw/prog/index.php/%E6%AD%A3% E8%A6%8F%E5%8C%96%E8%A1%A8%E7%A4%BA %E6%B3%95 18
- 19. REFERENCE 正則表達式語法 https://msdn.microsoft.com/zh- cn/library/ae5bf541(v=vs.100).aspx Regular Expression Library http://www.regexlib.com/?AspxAutoDetectCookieSuppor t=1 Regular expression 常用驗證 | 程式設計筆記 http://readily-notes.blogspot.tw/2010/09/regex.html 19
- 20. REFERENCE 37 TestedPHP, Perl, and JavaScript Regular Expressions http://www.virtuosimedia.com/dev/php/37-tested-php- perl-and-javascript-regular-expressions 20
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