Може ли някой да обясни подробно как точно работи Regex кода от изпита на 27.072014 ? Би било полезно.
var regex = /<a\s+([^>]+\s+)?href\s*=\s*('([^']*)'|"([^"]*)|([^\s>]+))[^>]*>/g;
http://www.lynda.com/Regular-Expressions-tutorials/Using-Regular-Expressions/85870-2.html
Ето този курс е много полезен. Има го по торент сайтовете, препоръчвам ти да си го свалиш и изгледаш. Защото обяснението на този regex ще отнеме доста време, и незнам дали ще успея да ти го обясня, така че да го разбереш, след този курс ще го разбереш с 1 поглед.
Поздрави
NODE EXPLANATION -------------------------------------------------------------------------------- /<a '/<a' -------------------------------------------------------------------------------- \s+ whitespace (\n, \r, \t, \f, and " ") (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- ( group and capture to \1 (optional (matching the most amount possible)): -------------------------------------------------------------------------------- [^>]+ any character except: '>' (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- \s+ whitespace (\n, \r, \t, \f, and " ") (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- )? end of \1 (NOTE: because you are using a quantifier on this capture, only the LAST repetition of the captured pattern will be stored in \1) -------------------------------------------------------------------------------- href 'href' -------------------------------------------------------------------------------- \s* whitespace (\n, \r, \t, \f, and " ") (0 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- = '=' -------------------------------------------------------------------------------- \s* whitespace (\n, \r, \t, \f, and " ") (0 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- ( group and capture to \2: -------------------------------------------------------------------------------- ' '\'' -------------------------------------------------------------------------------- ( group and capture to \3: -------------------------------------------------------------------------------- [^']* any character except: ''' (0 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- ) end of \3 -------------------------------------------------------------------------------- ' '\'' -------------------------------------------------------------------------------- | OR -------------------------------------------------------------------------------- " '"' -------------------------------------------------------------------------------- ( group and capture to \4: -------------------------------------------------------------------------------- [^"]* any character except: '"' (0 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- ) end of \4 -------------------------------------------------------------------------------- | OR -------------------------------------------------------------------------------- ( group and capture to \5: -------------------------------------------------------------------------------- [^\s>]+ any character except: whitespace (\n, \r, \t, \f, and " "), '>' (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- ) end of \5 -------------------------------------------------------------------------------- ) end of \2 -------------------------------------------------------------------------------- [^>]* any character except: '>' (0 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- > '>'
Тук също може да погледнеш малко обяснения :) ->>> http://www.myezapp.com/apps/dev/regexp/show.ws
Можеш да използваш този сайт http://regex101.com/ ... Въвеждаш твоя regex в полето "REGULAR EXPRESSION" и след това в дясно има подробни обяснения в "EXPLANATION".
За твоя случай ето какво излиза....
/<a\s+([^>]+\s+)?href\s*=\s*('([^']*)'|"([^"]*)|([^\s>]+))[^>]*>/g
<a matches the characters <a literally (case sensitive)
\s+ match any white space character [\r\n\t\f ]
Quantifier: Between one and unlimited times, as many times as possible, giving back as needed [greedy]
1st Capturing group ([^>]+\s+)?
Quantifier: Between zero and one time, as many times as possible, giving back as needed [greedy]
Note: A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
[^>]+ match a single character not present in the list below
Quantifier: Between one and unlimited times, as many times as possible, giving back as needed [greedy]
> a single character in the list > literally (case sensitive)
\s+ match any white space character [\r\n\t\f ]
Quantifier: Between one and unlimited times, as many times as possible, giving back as needed [greedy]
href matches the characters href literally (case sensitive)
\s* match any white space character [\r\n\t\f ]
Quantifier: Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
= matches the character = literally
\s* match any white space character [\r\n\t\f ]
Quantifier: Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
2nd Capturing group ('([^']*)'|"([^"]*)|([^\s>]+))
1st Alternative: '([^']*)'
' matches the character ' literally
3rd Capturing group ([^']*)
[^']* match a single character not present in the list below
Quantifier: Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
' the literal character '
' matches the character ' literally
2nd Alternative: "([^"]*)
" matches the character " literally
4th Capturing group ([^"]*)
[^"]* match a single character not present in the list below
Quantifier: Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
" the literal character "
3rd Alternative: ([^\s>]+)
5th Capturing group ([^\s>]+)
[^\s>]+ match a single character not present in the list below
Quantifier: Between one and unlimited times, as many times as possible, giving back as needed [greedy]
\s match any white space character [\r\n\t\f ]
> a single character in the list > literally (case sensitive)
[^>]* match a single character not present in the list below
Quantifier: Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
> a single character in the list > literally (case sensitive)
> matches the characters > literally
g modifier: global. All matches (don't return on first match)