Using regexp with an html string to extract text - regex

I have the following html string:
F.V.Adamian, G.G.Akopian
I want to form a single plain text string with the author names so that it looks something like (I can fine tune the punctuation later):
F.V.Adamian, G.G.Akopian.
I'm trying to use 'regexp' in Matlab. When I do the following:
regexpi(htmlstring,'">.*</a>','match')
I get:
">F.V.Adamian</a>, G.G.Akopian,
Why? I'm trying to get it to continuously output (hence I did not use the 'once' operator) all characters between "> and , which is the author's name. It works fine for the first one but not for the second. I am happy to truncate the "> and with a regexprep(regexpstring,'','') later.
I see that regexprep(htmlstr, '<.*?>','') works and does what I want. But I don't get it...

In .*? the ? is telling the .* to be lazy as opposed to greedy. By default, .* will try to match the largest thing it can. When you add the ? it instead goes for the smallest thing it can
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Related

How to linebreak in REGEX with brackets

I got a list of data like exactly like that
51.9499, 7.555780000000027; 51.49705, 9.389030000000048; 51.249182, 6.991165099999989; 47.3163508, 11.09513949999996; 51.33424979999999, 12.574196000000029; 50.0297493, 19.196331099999952; 47.8270212, 16.25014150000004;
and I want to beautify it a bit by having linebreaks behind the "; " so it would rather look like
51.9499, 7.555780000000027;
51.49705, 9.389030000000048;
51.249182, 6.991165099999989;
...
I am using Adobe Brackets and I am trying to put a hard linebreak into the replace dialogue but that doesn't work - what would instead work?
In the replace bar, click on the .* icon to change the replace method to regular expression.
Then you can use ;\s* replace with ;\n to beautify your code accordingly.
You can see an example of this regex being run here.
Outputs the following:
51.9499, 7.555780000000027;
51.49705, 9.389030000000048;
51.249182, 6.991165099999989;
47.3163508, 11.09513949999996;
51.33424979999999, 12.574196000000029;
50.0297493, 19.196331099999952;
47.8270212, 16.25014150000004;

How to find "complicated" URLs in a text file

I'm using the following regex to find URLs in a text file:
/http[s]?://(?:[a-zA-Z]|[0-9]|[$-_#.&+]|[!*\(\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+/
It outputs the following:
http://rda.ucar.edu/datasets/ds117.0/.
http://rda.ucar.edu/datasets/ds111.1/.
http://www.discover-earth.org/index.html).
http://community.eosdis.nasa.gov/measures/).
Ideally they would print out this:
http://rda.ucar.edu/datasets/ds117.0/
http://rda.ucar.edu/datasets/ds111.1/
http://www.discover-earth.org/index.html
http://community.eosdis.nasa.gov/measures/
Any ideas on how I should tweak my regex?
Thank you in advance!
UPDATE - Example of the text would be:
this is a test http://rda.ucar.edu/datasets/ds117.0/. and I want this to be copied over http://rda.ucar.edu/datasets/ds111.1/. http://www.discover-earth.org/index.html). http://community.eosdis.nasa.gov/measures/).
This will trim your output containing trail characters, ) .
import re
regx= re.compile(r'(?m)[\.\)]+$')
print(regx.sub('', your_output))
And this regex seems workable to extract URL from your original sample text.
https?:[\S]*\/(?:\w+(?:\.\w+)?)?
Demo,,, ( edited from https?:[\S]*\/)
Python script may be something like this
ss=""" this is a test http://rda.ucar.edu/datasets/ds117.0/. and I want this to be copied over http://rda.ucar.edu/datasets/ds111.1/. http://www.discover-earth.org/index.html). http://community.eosdis.nasa.gov/measures/). """
regx= re.compile(r'https?:[\S]*\/(?:\w+(?:\.\w+)?)?')
for m in regx.findall(ss):
print(m)
So for the urls you have here:
https://regex101.com/r/uSlkcQ/4
Pattern explanation:
Protocols (e.g. https://)
^[A-Za-z]{3,9}:(?://)
Look for recurring .[-;:&=+\$,\w]+-class (www.sub.domain.com)
(?:[\-;:&=\+\$,\w]+\.?)+`
Look for recurring /[\-;:&=\+\$,\w\.]+ (/some.path/to/somewhere)
(?:\/[\-;:&=\+\$,\w\.]+)+
Now, for your special case: ensure that the last character is not a dot or a parenthesis, using negative lookahead
(?!\.|\)).
The full pattern is then
^[A-Za-z]{3,9}:(?://)(?:[\-;:&=\+\$,\w]+\.?)+(?:\/[\-;:&=\+\$,\w\.]+)+(?!\.|\)).
There are a few things to improve or change in your existing regex to allow this to work:
http[s]? can be changed to https?. They're identical. No use putting s in its own character class
[a-zA-Z]|[0-9]|[$-_#.&+]|[!*\(\),] You can shorten this entire thing and combine character classes instead of using | between them. This not only improves performance, but also allows you to combine certain ranges into existing character class tokens. Simplifying this, we get [a-zA-Z0-9$-_#.&+!*\(\),]
We can go one step further: a-zA-Z0-9_ is the same as \w. So we can replace those in the character class to get [\w$-#.&+!*\(\),]
In the original regex we have $-_. This creates a range so it actually inclues everything between $ and _ on the ASCII table. This will cause unwanted characters to be matched: $%&'()*+,-./0123456789:;<=>?#ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_. There are a few options to fix this:
[-\w$#.&+!*\(\),] Place - at the start of the character class
[\w$#.&+!*\(\),-] Place - at the end of the character class
[\w$\-#.&+!*\(\),] Escape - such that you have \- instead
You don't need to escape ( and ) in the character class: [\w$#.&+!*(),-]
[0-9a-fA-F][0-9a-fA-F] You don't need to specify [0-9a-fA-F] twice. Just use a quantifier like so: [0-9a-fA-F]{2}
(?:%[0-9a-fA-F][0-9a-fA-F]) The non-capture group isn't actually needed here, so we can drop it (it adds another step that the regex engine needs to perform, which is unnecessary)
So the result of just simplifying your existing regex is the following:
https?://(?:[$\w#.&+!*(),-]|%[0-9a-fA-F]{2})+
Now you'll notice it doesn't match / so we need to add that to the character class. Your regex was matching this originally because it has an improper range $-_.
https?://(?:[$\w#.&+!*(),/-]|%[0-9a-fA-F]{2})+
Unfortunately, even with this change, it'll still match ). at the end. That's because your regex isn't told to stop matching after /. Even implementing this will now cause it to not match file names like index.html. So a better solution is needed. If you give me a couple of days, I'm working on a fully functional RFC-compliant regex that matches URLs. I figured, in the meantime, I would at least explain why your regex isn't working as you'd expect it to.
Thanks all for the responses. A coworker ended up helping me with it. Here is the solution:
des_links = re.findall('http[s]?://(?:[a-zA-Z]|[0-9]|[$-_#.&+]|[!*\(\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+', des)
for i in des_links:
tmps = "/".join(i.split('/')[0:-1])
print(tmps)

How do I use regex to return text following specific prefixes?

I'm using an application called Firemon which uses regex to pull text out of various fields. I'm unsure what specific version of regex it uses, I can't find a reference to this in the documentation.
My raw text will always be in the following format:
CM: 12345
APP: App Name
BZU: Dept Name
REQ: First Last
JST: Text text text text.
CM will always be an integer, JST will be sentence that may span multiple lines, and the other fields will be strings that consist of 1-2 words - and there's always a return after each section.
The application, Firemon, has me create a regex entry for each field. Something simple that looks for each prefix and then a return should work, because I return after each value. I've tried several variations, such as "BZU:\s*(.*)", but can't seem to find something that works.
EDIT: To be clear I'm trying to get the value after each prefix. Firemon has a section for each field. "APP" for example is a field. I need a regex example to find "APP:" and return the text after it. So something as simple as regex that identifies "APP:", and grabs everything after the : and before the return would probably work.
You can use (?=\w+ )(.*)
Positive lookahead will remove prefix and space character from match groups and you will in each match get text after space.
I am a little late to the game, but maybe this is still an issue.
In the more recent versions of FireMon, sample regexes are provided. For instance:
jst:\s*([^;]?)\s;
will match on:
jst:anything in here;
and result in
anything in here

How to extract FirstName and LastName from html tags with regex?

I have response body which contains
"<h3 class="panel-title">Welcome
First Last </h3>"
I want to fetch 'First Last' as a output
The regular expression I have tried are
"Welcome(\s*([A-Za-z]+))(\s*([A-Za-z]+))"
"Welcome \s*([A-Za-z]+)\s*([A-Za-z]+)"
But not able to get the result. If I remove the newline and take it as
"<h3 class="panel-title">Welcome First Last </h3>" it is detecting in online regex maker.
I suspect your problem is the carriage return between "Welcome" and the user name. If you use the "single-line mode" flag (?s) in your regex, it will ignore newlines. Try these:
(?s)Welcome(\s*([A-Za-z]+))(\s*([A-Za-z]+))
(?s)Welcome \s*([A-Za-z]+)\s*([A-Za-z]+)
(this works in jMeter and any other java or php based regex, but not in javascript. In the comments on the question you say you're using javascript and also jMeter - if it is a jMeter question, then this will help. if javaScript, try one of the other answers)
Well, usually I don't recommend regex for this kind of work. DOM manipulation plays at its best.
but you can use following regex to yank text:
/(?:<h3.*?>)([^<]+)(?:<\/h3>)/i
See demo at https://regex101.com/r/wA2sZ9/1
This will extract First and Last names including extra spacing. I'm sure you can easily deal with spaces.
In jmeter reg exp extractor you can use:
<h3 class="panel-title">Welcome(.*?)</h3>
Then take value using $1$.
In the data you shown welcome is followed by enter.If actually its part of response then you have to use \n.
<h3 class="panel-title">Welcome\n(.*?)</h3>
Otherwise above one is enough.
First verify this in jmeter using regular expression tester of response body.
Welcome([\s\S]+?)<
Try this, it will definitely work.
Regular expressions are greedy by default, try this
Welcome\s*([A-Za-z]+)\s*([A-Za-z]+)
Groups 1 and 2 contain your data
Check it here

Regexp for finding tags without nested tags

I'm trying to write a regexp which will help to find non-translated texts in html code.
Translated texts means that they are going through special tag: or through construction: ${...}
Ex. non-translated:
<h1>Hello</h1>
Translated texts are:
<h1><fmt:message key="hello" /></h1>
<button>${expression}</button>
I've written the following expression:
\<(\w+[^>])(?:.*)\>([^\s]+?)\</\1\>
It finds correct strings like:
<p>text<p>
Correctly skips
<a><fmt:message key="common.delete" /></a>
But also catches:
<li><p><fmt:message key="common.delete" /></p></li>
And I can't figure out how to add exception for ${...} strings in this expression
Can anybody help me?
If I understand you properly, you want to ensure the data inside the "tag" doesn't contain fmt:messsage or ${....}
You might be able to use a negative-lookahead in conjuction with a . to assert that the characters captured by the . are not one of those cases:
/<(\w+)[^>]*>(?:(?!<fmt:message|\$\{|<\/\1>).)*<\/\1>/i
If you want to avoid capturing any "tags" inside the tag, you can ignore the <fmt:message portion, and just use [^<] instead of a . - to match only non <
/<(\w+)[^>]*>(?:(?!\$\{)[^<])*<\/\1>/i
Added from comment If you also want to exclude "empty" tags, add another negative-lookahead - this time (?!\s*<) - ensure that the stuff inside the tag is not empty or only containing whitespace:
/<(\w+)[^>]*>(?!\s*<)(?:(?!\$\{)[^<])*<\/\1>/i
If the format is simple as in your examples you can try this:
<(\w+)>(?:(?!<fmt:message).)+</\1>
Rewritten into a more formal question:
Can you match
aba
but not
aca
without catching
abcba ?
Yes.
FSM:
Start->A->B->A->Terminate
Insert abcba and run it
Start is ready for input.
a -> MATCH, transition to A
b -> MATCH, transition to B
c -> FAIL, return fail.
I've used a simple one like this with success,
<([^>]+)[^>]*>([^<]*)</\1>
of course if there is any CDATA with '<' in those it's not going to work so well. But should do fine for simple XML.
also see
https://blog.codinghorror.com/parsing-html-the-cthulhu-way/
for a discussion of using regex to parse html
executive summary: don't