regular expression 7c

1Let regex;
2/* shorthand character classes */
3regex = /d/; // matches any digit, short for [0-9]
4regex = /D/; // matches non-digits, short for [^0-9]
5regex = /S/; // matches non-white space character
6regex = /s/; // matches any white space character
7regex = /w/; // matches character, short for [a-zA-Z_0-9]
8regex = /W/; // matches non-word character [^w]
9regex = /b/; // Matches a word boundary where a word character is [a-zA-Z0-9_]
10These meta characters boast a pre-defined meaning and make various typical patterns easier to use.
11/* matching using quantifiers */
12regex= /X./; // matches any character
13regex= /X*/; // Matches zero or several repetitions of letter X, is short for {0,}
14regex= /X+-/; // matches one or more repetitions of letter X, is short for {1,}
15regex= /X?/; // finds no or exactly one letter X, is short for is short for {0,1}.
16regex= // d{3}; // matches three digits. {} describes the order of the preceding liberal
17regex= // d{1,4} ; // means d must occur at least once and at a maximum of four
18A quantifies helps developers to define how often an element occurs.
19/* character ranges */
20regex = /[a-z]/; // matches all lowercase letters
21regex = /[A-Z]/; // matches all uppercase letters
22regex = /[e-l]/; // matches lowercase letters e to l (inclusive)
23regex = /[F-P]/; // matches all uppercase letters F to P (inclusive)
24regex = /[0-9]/; // matches all digits
25regex = /[5-9]/; // matches any digit from 5 to 9 (inclusive)
26regex = / [a-d1-7]/; // matches a letter between a and d and figures from 1 to 7, but not d1
27regex = /[a-zA-Z]/; // matches all lowercase and uppercase letters
28regex = /[^a-zA-Z]/; // matches non-letters
29/* matching using anchors */
30regex = / ^The/; // matches any string that starts with “The”
31regex = / end$/; // matches a string that ends with end
32regex = / ^The end$/; // exact string match starting with “The” and ending with “End”
33/* escape characters */
34regex = / a/; // match a bell or alarm
35regex = / e/; // matches an escape
36regex = / f/; // matches a form feed
37regex = / n/; // matches a new line
38regex = / Q…E/; // ingnores any special meanings in what is being matched
39regex = / r/; // matches a carriage return
40regex = / v/; // matches a vertical tab
41It is critical to note that escape characters are case sensitive
42/* matching using flags */
43regex = / i/; // ignores the case in pattern ( upper and lower case allowed)
44regex = / m/; // multi-line match
45regex = / s/; // match new lines
46regex = / x/; // allow spaces and comments
47regex = / j/; // duplicate group names allowed
48regex = / U/; // ungreedy match

1Let regex;
2/* shorthand character classes */
3regex = /d/; // matches any digit, short for [0-9]
4regex = /D/; // matches non-digits, short for [^0-9]
5regex = /S/; // matches non-white space character
6regex = /s/; // matches any white space character
7regex = /w/; // matches character, short for [a-zA-Z_0-9]
8regex = /W/; // matches non-word character [^w]
9regex = /b/; // Matches a word boundary where a word character is [a-zA-Z0-9_]
10These meta characters boast a pre-defined meaning and make various typical patterns easier to use.
11/* matching using quantifiers */
12regex= /X./; // matches any character
13regex= /X*/; // Matches zero or several repetitions of letter X, is short for {0,}
14regex= /X+-/; // matches one or more repetitions of letter X, is short for {1,}
15regex= /X?/; // finds no or exactly one letter X, is short for is short for {0,1}.
16regex= // d{3}; // matches three digits. {} describes the order of the preceding liberal
17regex= // d{1,4} ; // means d must occur at least once and at a maximum of four
18A quantifies helps developers to define how often an element occurs.
19/* character ranges */
20regex = /[a-z]/; // matches all lowercase letters
21regex = /[A-Z]/; // matches all uppercase letters
22regex = /[e-l]/; // matches lowercase letters e to l (inclusive)
23regex = /[F-P]/; // matches all uppercase letters F to P (inclusive)
24regex = /[0-9]/; // matches all digits
25regex = /[5-9]/; // matches any digit from 5 to 9 (inclusive)
26regex = / [a-d1-7]/; // matches a letter between a and d and figures from 1 to 7, but not d1
27regex = /[a-zA-Z]/; // matches all lowercase and uppercase letters
28regex = /[^a-zA-Z]/; // matches non-letters
29/* matching using anchors */
30regex = / ^The/; // matches any string that starts with “The”
31regex = / end$/; // matches a string that ends with end
32regex = / ^The end$/; // exact string match starting with “The” and ending with “End”
33/* escape characters */
34regex = / a/; // match a bell or alarm
35regex = / e/; // matches an escape
36regex = / f/; // matches a form feed
37regex = / n/; // matches a new line
38regex = / Q…E/; // ingnores any special meanings in what is being matched
39regex = / r/; // matches a carriage return
40regex = / v/; // matches a vertical tab
41It is critical to note that escape characters are case sensitive
42/* matching using flags */
43regex = / i/; // ignores the case in pattern ( upper and lower case allowed)
44regex = / m/; // multi-line match
45regex = / s/; // match new lines
46regex = / x/; // allow spaces and comments
47regex = / j/; // duplicate group names allowed
48regex = / U/; // ungreedy match
49

1/findme/
2Characters \, ., \cX, \d, \D, \f, \n, \r, \s, \S, \t, \v, \w, \W, \0, \xhh, \uhhhh, \uhhhhh, [\b]	
3Assertions 	^, $, x(?=y), x(?!y), (?<=y)x, (?<!y)x, \b, \B
4Groups 		(x), (?:x), (?<Name>x), x|y, [xyz], [^xyz], \Number	
5Quantifiers *, +, ?, x{n}, x{n,}, x{n,m}
6Unicode \p{UnicodeProperty}, \P{UnicodeProperty}
7javascript
8let re = /findme/
9let defaults = new RegExp('compiled'); 
10defaults = { dotAll: false, flags: "", global: false, ignoreCase: false, falselastIndex: 0, multiline: false, source: "abc", sticky: false, unicode: false}

1\b0*([a-zA-Z1-9][a-zA-Z0-9]*|0)\b$
2

1import re
2reload (re)
3
4r = re.compile("([0-9]+)([a-zA-Z]+)([0-9]+)")
5m = r.match("123ab1234")
6if m:
7    print m.group(1)
8    print m.group(2)
9    print m.group(3)
10
11else:
12    print "no match"
13