Regular expressions 정규표현 식
정규표현식 작성
http://zvon.org/comp/r/tut-Regexp.html#Pages~Contents
Page 1
Regular expressions are case sensitive. Therefore Case 1 will find the specified text, but Case 2 will not.
Source
Hello, world! |
Case 1
Regular Expression: | Hello |
First match: | Hello, world! |
All matches: | Hello, world! |
Case 2
Regular Expression: | hello |
First match: | Hello, world! |
All matches: | Hello, world! |
Page 2
Each character inside the search pattern is significant including whitespace characters (space, tab, new line).
Source
Hello, world! |
Case 1
Regular Expression: | Hello, world |
First match: | Hello, world! |
All matches: | Hello, world! |
Case 2
Regular Expression: | Hello, world |
First match: | Hello, world! |
All matches: | Hello, world! |
Page 3
Some characters have special meanings. Character ^ matches the beginning of the line (Case 1) while dollar sign $ the end of the line (Case 2)
Source
who is who |
Case 1
Regular Expression: | ^who |
First match: | who is who |
All matches: | who is who |
Case 2
Regular Expression: | who$ |
First match: | who is who |
All matches: | who is who |
Page 4
If literal value of a special character is required, it must be escaped with a backslash \. Case 1 does not match anything as both characters a special, Case 2 matches all $, Case 3 matches $ only if it is the first and Case 4 the last character. Backslash has special meaning and must be also escaped for literal use (Case 5).
Source
$12$ \-\ $25$ |
Case 1
Regular Expression: | ^$ |
First match: | $12$ \-\ $25$ |
All matches: | $12$ \-\ $25$ |
Case 2
Regular Expression: | \$ |
First match: | $12$ \-\ $25$ |
All matches: | $12$ \-\ $25$ |
Case 3
Regular Expression: | ^\$ |
First match: | $12$ \-\ $25$ |
All matches: | $12$ \-\ $25$ |
Case 4
Regular Expression: | \$$ |
First match: | $12$ \-\ $25$ |
All matches: | $12$ \-\ $25$ |
Case 5
Regular Expression: | \\ |
First match: | $12$ \-\ $25$ |
All matches: | $12$ \-\ $25$ |
Page 5
Point . matches any character.
Source
Regular expressions are powerful!!! |
Case 1
Regular Expression: | . |
First match: | Regular expressions are powerful!!! |
All matches: | Regular expressions are powerful!!! |
Case 2
Regular Expression: | ...... |
First match: | Regular expressions are powerful!!! |
All matches: | Regular expressions are powerful!!! |
Page 6
The point must be escaped if literal meaning is required.
Source
O.K. |
Case 1
Regular Expression: | . |
First match: | O.K. |
All matches: | O.K. |
Case 2
Regular Expression: | \. |
First match: | O.K. |
All matches: | O.K. |
Case 3
Regular Expression: | \..\. |
First match: | O.K. |
All matches: | O.K. |
Page 7
Inside square brackets "[]" a list of characters can be provided. The expression matches if any of these characters is found. The order of characters is insignificant.(Case 3)
Source
How do you do? |
Case 1
Regular Expression: | [oyu] |
First match: | How do you do? |
All matches: | How do you do? |
Case 2
Regular Expression: | [dH]. |
First match: | How do you do? |
All matches: | How do you do? |
Case 3
Regular Expression: | [owy][yow] |
First match: | How do you do? |
All matches: | How do you do? |
Page 8
A range of characters can be specified with [ - ] syntax. Case 1 andCase 2 are equivalent. Several ranges can be given in one expression (Case 5).
Source
ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
Case 1
Regular Expression: | [C-K] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
Case 2
Regular Expression: | [CDEFGHIJK] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
Case 3
Regular Expression: | [a-d] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz 0123456789 |
Case 4
Regular Expression: | [2-6] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
Case 5
Regular Expression: | [C-Ka-d2-6] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz 0123456789 |
Page 9
If a character class starts with ^, then specified characters will not be selected
Source
ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
Case 1
Regular Expression: | [^CDghi45] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz 0123456789 |
Case 2
Regular Expression: | [^W-Z] |
First match: | ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 |
All matches: | ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz 0123456789 |
Page 10
Alternating text can be enclosed in parentheses and alternatives separated with |.
Source
Monday Tuesday Friday |
Case 2
Regular Expression: | (on|ues|rida) |
First match: | Monday Tuesday Friday |
All matches: | Monday Tuesday Friday |
Case 2
Regular Expression: | (Mon|Tues|Fri)day |
First match: | Monday Tuesday Friday |
All matches: | Monday Tuesday Friday |
Case 3
Regular Expression: | ..(id|esd|nd)ay |
First match: | Monday Tuesday Friday |
All matches: | Monday Tuesday Friday |
Page 11
Quantifiers specify how many times a character can occur. Star * (Case 1) matches zero or more times, plus + (Case 2) once or more times and question mark ? (Case 3) zero or once.
Source
aabc abc bc |
Case 1
Regular Expression: | a*b |
First match: | aabc abc bc |
All matches: | aabc abc bc |
Case 2
Regular Expression: | a+b |
First match: | aabc abc bc |
All matches: | aabc abc bc |
Case 3
Regular Expression: | a?b |
First match: | aabc abc bc |
All matches: | aabc abc bc |
Page 12
Several examples of "*" quantifier
Source
-@- *** -- "*" -- *** -@- |
Case 1
Regular Expression: | .* |
First match: | -@- *** -- "*" -- *** -@- |
All matches: | -@- *** -- "*" -- *** -@- |
Case 2
Regular Expression: | -A*- |
First match: | -@- *** -- "*" -- *** -@- |
All matches: | -@- *** -- "*" -- *** -@- |
Case 3
Regular Expression: | [-@]* |
First match: | -@- *** -- "*" -- *** -@- |
All matches: | -@- *** -- "*" -- *** -@- |
Page 13
Several examples of "+" quantifier
Source
-@@@- * ** - - "*" -- * ** -@@@- |
Case 1
Regular Expression: | \*+ |
First match: | -@@@- * ** - - "*" -- * ** -@@@- |
All matches: | -@@@- * ** - - "*" -- * ** -@@@- |
Case 2
Regular Expression: | -@+- |
First match: | -@@@- * ** - - "*" -- * ** -@@@- |
All matches: | -@@@- * ** - - "*" -- * ** -@@@- |
Case 3
Regular Expression: | [^ ]+ |
First match: | -@@@- * ** - - "*" -- * ** -@@@- |
All matches: | -@@@- * ** - - "*" -- * ** -@@@- |
Page 14
Several examples of "?" quantifier
Source
--XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
Case 1
Regular Expression: | -X?XX?X |
First match: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
All matches: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
Case 2
Regular Expression: | -@?@?@?- |
First match: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
All matches: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
Case 3
Regular Expression: | [^@]@?@ |
First match: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
All matches: | --XX-@-XX-@@-XX-@@@-XX-@@@@-XX-@@-@@- |
Page 15
Curly brackets enable precise specification of character repetitions. {m} matches precisely m times (Case 1), {m,n} matches minimaly m times and maximaly n times (Case 2) and {m,}matches minimaly m times(Case 3).
Source
One ring to bring them all and in the darkness bind them |
Case 1
Regular Expression: | .{5} |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 2
Regular Expression: | [els]{1,3} |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in thedarkness bind them |
Case 3
Regular Expression: | [a-z]{3,} |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in thedarkness bind them |
Page 16
Quantifiers "*", "+", and "?" are special cases of the bracket notation. "*" is equivalent to {0,} (Case 1, Case 2), "+" to {1,} (Case 3, Case 4), and "?" to {0,1} (Case 5, Case 6).
Source
AA ABA ABBA ABBBA |
Case 1
Regular Expression: | AB*A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Case 2
Regular Expression: | AB{0,}A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Case 3
Regular Expression: | AB+A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Case 4
Regular Expression: | AB{1,}A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Case 5
Regular Expression: | AB?A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Case 6
Regular Expression: | AB{0,1}A |
First match: | AA ABA ABBA ABBBA |
All matches: | AA ABA ABBA ABBBA |
Page 17
By default any subpattern matches as many times as possible. This behaviour is changed to matching the minimum number if quantifier is followed with the question mark. Compare "*" (Case 1) with "*?" (Case 2), "+" (Case 3) with "+?" (Case 4), and "?" (Case 5) with "??" (Case 6).
Source
One ring to bring them all and in the darkness bind them |
Case 1
Regular Expression: | r.* |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 2
Regular Expression: | r.*? |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 3 greedy
Regular Expression: | r.+ |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 4 lazy
Regular Expression: | r.+? |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 5
Regular Expression: | r.? |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Case 6
Regular Expression: | r.?? |
First match: | One ring to bring them all and in the darkness bind them |
All matches: | One ring to bring them all and in the darkness bind them |
Page 18
\w matches any word character ( alphanumeric plus "_" ). In some languages these letter abbreviations are not recognized. Use character classes ("[A-z0-9_]") instead (Case 5).
Source
A1 B2 c3 d_4 e:5 ffGG77--__-- |
Case 1
Regular Expression: | \w |
First match: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
All matches: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
Case 2
Regular Expression: | \w* |
First match: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
All matches: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
Case 3
Regular Expression: | [a-z]\w* |
First match: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
All matches: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
Case 4
Regular Expression: | \w{5} |
First match: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
All matches: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
Case 5
Regular Expression: | [A-z0-9_] |
First match: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
All matches: | A1 B2 c3 d_4 e:5 ffGG77--__-- |
Page 19
\W matches any non-word character (everything but alphanumeric plus "_" ). Compare Case 1 and Case 2. It is equivalent to "[^A-z0-9_]".
Source
AS _34:AS11.23 @#$ %12^* |
Case 1
Regular Expression: | \W |
First match: | AS _34:AS11.23 @#$ %12^* |
All matches: | AS _34:AS11.23 @#$ %12^* |
Case 2
Regular Expression: | \w |
First match: | AS _34:AS11.23 @#$ %12^* |
All matches: | AS _34:AS11.23 @#$ %12^* |
Case 3
Regular Expression: | [^A-z0-9_] |
First match: | AS _34:AS11.23 @#$ %12^* |
All matches: | AS _34:AS11.23 @#$ %12^* |
Page 20
\s matches white space characters: space, new line and tab. \S matches any non-whitespace character.
Source
Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Case 1
Regular Expression: | \s |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, When youngwas mountain under moon; Ere ring was made, orwrought was woe, It walked the forests long ago. |
Case 2
Regular Expression: | \S |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, Whenyoung was mountain under moon; Ere ringwas made, or wrought was woe, It walkedthe forests long ago. |
Page 21
\d matches any digit and \D anything else. Compare Case 1 andCase 2. Use "[0-9]" if your programming language does not support this abbreviation (Case 3).
Source
Page 123; published: 1234 id=12#24@112 |
Case 1
Regular Expression: | \d |
First match: | Page 123; published: 1234 id=12#24@112 |
All matches: | Page 123; published: 1234id=12#24@112 |
Case 2
Regular Expression: | \D |
First match: | Page 123; published: 1234 id=12#24@112 |
All matches: | Page 123; published: 1234id=12#24@112 |
Case 3
Regular Expression: | [0-9] |
First match: | Page 123; published: 1234 id=12#24@112 |
All matches: | Page 123; published: 1234id=12#24@112 |
Page 22
\b matches a word boundary. A word boundary (\b) is defined as a spot between two characters that has a \w on one side of it and a \W on the other side of it (in either order).
Source
Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Case 1
Regular Expression: | \b. |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, Whenyoung was mountain under moon; Ere ring wasmade, or wrought was woe, It walked the forestslong ago. |
Case 2
Regular Expression: | .\b |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, Whenyoung was mountain under moon; Ere ring wasmade, or wrought was woe, It walked the forestslong ago. |
Page 23
\B matches a non (word boundary). A word boundary (\b) is defined as a spot between two characters that has a \w on one side of it and a \W on the other side of it (in either order).
Source
Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Case 1
Regular Expression: | \B. |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, Whenyoung was mountain under moon; Ere ringwas made, or wrought was woe, It walked theforests long ago. |
Case 2
Regular Expression: | .\B |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, Whenyoung was mountain under moon; Ere ringwas made, or wrought was woe, It walked theforests long ago. |
Page 24
\A matches the beginning of string. It is similar to ^, but ^ will match after each newline, if multiline strings are considered. Similarly, \Z matches only at the end of the string or before newline at the end of it. It is similar to $, but $ will match before each newline.
Source
Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Case 1
Regular Expression: | \A... |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Case 2
Regular Expression: | ...\Z |
First match: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
All matches: | Ere iron was found or tree was hewn, When young was mountain under moon; Ere ring was made, or wrought was woe, It walked the forests long ago. |
Page 25
(?=<pattern>) will look ahead if the pattern exists, but will not include it in the hit.
Source
AAAX---aaax---111 |
Case 1
Regular Expression: | \w+(?=X) |
First match: | AAAX---aaax---111 |
All matches: | AAAX---aaax---111 |
Case 2
Regular Expression: | \w+ |
First match: | AAAX---aaax---111 |
All matches: | AAAX---aaax---111 |
Case 3
Regular Expression: | \w+(?=\w) |
First match: | AAAX---aaax---111 |
All matches: | AAAX---aaax---111 |
Page 26
(?!<pattern>) will look ahead if the pattern exists. If it does there will be no hit.
Source
AAAX---AAA |
Case 1
Regular Expression: | AAA(?!X) |
First match: | AAAX---AAA |
All matches: | AAAX---AAA |
Case 2
Regular Expression: | AAA |
First match: | AAAX---AAA |
All matches: | AAAX---AAA |
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