A string contain many urls, how to get urls start not with [url], and end not with [/url]
Example:
A string contain many urls: https://stackoverflow.com/1 [url]https://stackoverflow.com/2[/url] https://stackoverflow.com/3 [url]https://stackoverflow.com/4[/url], how to get match urls?
In this sample, need only return https://stackoverflow.com/1 and https://stackoverflow.com/3.
I will underline only the regex expression as it is very important to get the urls. So it will be:
(?!\[url\])\s+\bhttp:\/\/stackoverflow.com\/\d\s+(?<!\[\/url\])
you can see the result in this Url by using the php function preg_match_all
but before that let's understand every part of it (you can find this in the same site)
(?!\[url\])\s+\bhttp:\/\/stackoverflow.com\/\d\s+(?<!\[\/url\])
(?!\[url\]) Negative Lookahead - Assert that it is impossible to match the regex below
\[ matches the character [ literally \] matches the character ] literally\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]
\b assert position at a word boundary (^\w|\w$|\W\w|\w\W)
http: matches the characters http: literally (case sensitive)
\/ matches the character / literally
\/ matches the character / literally
stackoverflow matches the characters stackoverflow literally (case sensitive)
. matches any character (except newline)
com matches the characters com literally (case sensitive)
/ matches the character / literally
\d match a digit [0-9]
\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]
(?<!\[\/url\]) Negative Lookbehind - Assert that it is impossible to match the regex below
\[ matches the character [ literally\/ matches the character / literally \] matches the character ] literallyFinally you need to use the php function as follow:
preg_match_all("(?!\[url\])\s+\bhttp:\/\/stackoverflow.com\/\d\s+(?<!\[\/url\])", $input_lines, $output_array);
$input_lines is the variable that holds your string
$output_array the arrays that holds the urls
(?<!\[url\])(?![^\s]+\[\/url\])http[^\s]*
This will grab the all the URLs not enclosed in the tags you mentioned ([url] and [\url]). Note that this works for every URL, not just the one you listed (i.e http://stackoverflow.com), which I think is what you want. You can see the explanations and live demo for each rule on Regex101 - Link: https://regex101.com/r/wN9aX0/3
http://stackoverflow.com/5[/url], i.e. if it doesn't start with [url] but ends with [/url] - not sure if this is OK with the OP.
This is a little complicated pattern and probably won't work for all cases, but will work for most. If it doesn't work in a case you want it to work, I could tweak it further:
(?<!(\[url\]))[\s.:]((http|https)(:\/\/))?([[:alnum:]\-_]*)(([\.])([[:alnum:]\-_]*)){1,}([\/]([[:alnum:]\-_]*))*[.:;\s]((?!\[\/url\]))
This help you :
var patt =/(?:\bhttp:\/\/stackoverflow.com\/\d{1,})(?!\[\/url\])/;
Example :
<html>
<head></head>
<body>
<script>
var patt =/(?:\bhttp:\/\/stackoverflow.com\/\d{1,})(?!\[\/url\])/;
var str = "http://stackoverflow.com/2";
if(patt.test(str))
alert("Valid");
else
alert("Invalid");
</script>
</body>
</html>
http? See my answer below if so.