Regular expressions 정규표현 식

http://regexr.com/

정규표현식 작성

http://regexone.com/

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:

Hodo 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:

aababbc

Case 2

Regular Expression:

a+b

First match:

aabc abc bc

All matches:

aababc bc

Case 3

Regular Expression:

a?b

First match:

aabc abc bc

All matches:

aababbc

 

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 1Case 2), “+” to {1,} (Case 3Case 4), and “?” to {0,1} (Case 5Case 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:

Erirowafounotrewahewn, Whenyounwamountaiundemoon; Errinwasmade, owroughwawoe, Iwalkethforestslonago.

 

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:

Erirowafounotrewahewn, Whenyounwamountaiundemoon; Erringwamade, owroughwawoe, Iwalketheforestlonago.

 

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:

AAAXaaax111

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