I'm having a markdown file wich is a little bit broken: the links and images which are too long have line-breaks in it. I would like to remove line-breaks from them.
Example:
from:
See for example the
[installation process for Ubuntu
Trusty](https://wiki.diasporafoundation.org/Installation/Ubuntu/Trusty). The
project offers a Vagrant installation too, but the documentation only admits
that you know what you do, that you are a developer. If it is difficult to
_A pretty decentralized network (Source: <https://diasporafoundation.org/>)_
to:
See for example the
[installation process for Ubuntu Trusty](https://wiki.diasporafoundation.org/Installation/Ubuntu/Trusty). The
project offers a Vagrant installation too, but the documentation only admits
that you know what you do, that you are a developer. If it is difficult to
_A pretty decentralized network (Source: <https://diasporafoundation.org/>)_
As you can see in this snippet, I managed to match the all links and images with the right pattern: https://regex101.com/r/uL8pO4/2
But now, what is the syntax in Python to use a string method like string.trim() on what I have captured with regular expression?
For the moment, I'm stuck with this:
fix_newlines = re.compile(r'\[([\w\s*:/]*)\]\(([^()]+)\)')
# Capture the links and remove line-breaks from their urls
# Something like r'[\1](\2)'.trim() ??
post['content'] = fix_newlines.sub(r'[\1](\2)', post['content'])
Edit: I updated the example to be more explicit about my problem.
Thank you for your answer
strip would work similar to functionality of trim. As you would need to trim the new lines, use strip('\n'),
fin.readline.strip('\n')
This will work also:
>>> s = """
... 
... """
>>> new_s = "".join(s.strip().split('\n'))
>>> new_s
''
>>>
Often times built-in string functions will do, and are easier to read than figuring out regexes. In this case strip removes leading and trailing space, then split returns a list of items between newlines, and join puts them back together in a single string.
Alright, I finally found what I was searching. With the snippet below, I could capture a string with a regex and then apply the treatment on each of them.
def remove_newlines(match):
return "".join(match.group().strip().split('\n'))
links_pattern = re.compile(r'\[([\w\s*:/\-\.]*)\]\(([^()]+)\)')
post['content'] = links_pattern.sub(remove_newlines, post['content'])
Thank you for your answers and sorry if my question wasn't explicit enough.
Related
I'm really sorry for asking because there are some questions like this around. But can't get the answer fixed to make problem.
This are the input lines (e.g. from a config file)
profile2.name=share2
profile8.name=share8
profile4.name=shareSSH
profile9.name=share9
I just want to extract the values behind the = sign with Python 3.9. regex.
I tried this on regex101.
^profile[0-9]\.name=(.*?)
But this gives me the variable name including the = sign as result; e.g. profile2.name=. But I want exactly the inverted opposite.
The expected results (what Pythons re.find_all() return) are
['share2', 'share8', 'shareSSH', 'share9']
Try pattern profile\d+\.name=(.*), look at Regex 101 example
import re
re.findall('profile\d+\.name=(.*)', txt)
# output
['share2', 'share8', 'shareSSH', 'share9']
But this problem doesn't necessarily need regex, split should work absolutely fine:
Try removing the ? quantifier. It will make your capture group match an empty st
regex101
My input string contains various entities like this:
conn_type://host:port/schema#login#password
I want to find out all of them using regex in python.
As of now, I am able to find them one by one, like
conn_type=re.search(r'[a-zA-Z]+',test_string)
if (conn_type):
print "conn_type:", conn_type.group()
next_substr_len = conn_type.end()
host=re.search(r'[^:/]+',test_string[next_substr_len:])
and so on.
Is there a way to do it without if and else?
I expect there to be some way, but not able to find it. Please note that every entity regex is different.
Please help, I don't want to write a boring code.
Why don't you use re.findall?
Here is an example:
import re;
s = 'conn_type://host:port/schema#login#password asldasldasldasdasdwawwda conn_type://host:port/schema#login#email';
def get_all_matches(s):
matches = re.findall('[a-zA-Z]+_[a-zA-Z]+:\/+[a-zA-Z]+:+[a-zA-Z]+\/+[a-zA-Z]+#+[a-zA-Z]+#[a-zA-Z]+',s);
return matches;
print get_all_matches(s);
this will return a list full of matches to your current regex as seen in this example which in this case would be:
['conn_type://host:port/schema#login#password', 'conn_type://host:port/schema#login#email']
If you need help making regex patterns in Python I would recommend using the following website:
A pretty neat online regex tester
Also check the re module's documentation for more on re.findall
Documentation for re.findall
Hope this helps!
>>>import re
>>>uri = "conn_type://host:port/schema#login#password"
>>>res = re.findall(r'(\w+)://(.*?):([A-z0-9]+)/(\w+)#(\w+)#(\w+)', uri)
>>>res
[('conn_type', 'host', 'port', 'schema', 'login', 'password')]
No need for ifs. Use findall or finditer to search through your collection of connection types. Filter the list of tuples, as need be.
If you like it DIY, consider creating a tokenizer. This is very elegant "python way" solution.
Or use a standard lib: https://docs.python.org/3/library/urllib.parse.html but note, that your sample URL is not fully valid: there is no schema 'conn_type' and you have two anchors in the query string, so urlparse wouldn't work as expected. But for real-life URLs I highly recommend this approach.
I wrote a script in Python for custom HTML page that finds a word within a string/line and highlights just that word with use of following tags where instance is the word that is searched for.
<b><font color=\"red\">"+instance+"</font></b>
With the following result:
I need to find a word (case insensitive) let's say "port" within a string that can be port, Port, SUPPORT, Support, support etc, which is easy enough.
pattern = re.compile(word, re.IGNORECASE)
find_all_instances = pattern.findall(string_to_search)
However my strings often contain 2 or more instances in single line, and I need to append
<b><font color=\"red\">"+instance+"</font></b> to each of those instances, without changing cases.
Problem with my approach, is that I am attempting to itterate over each of instances found with findall (exact match),
while multiple same matches can also be found within the string.
for instance in find_all_instances:
second_pattern = re.compile(instance)
string_to_search = second_pattern.sub("<b><font color=\"red\">"+instance+"</font></b>", string_to_search)
This results in following:
<b><font color="red"><b><font color="red"><b><font color="red">Http</font></b></font></b></font></b></font>
when I need
<b><font color="red">Http</font></b>
I was thinking, I would be able to avoid this if I was able to find out exact part of the string that the pattern.sub substitutes at the moment of doing it,
however I was not able to find any examples of that kind of usage, which leads me to believe that I am doing something very wrong.
If anyone have a way I could use to insert <b><font color="red">instance</font></b> without replacing instance for all matches(case insensitive), then I would be grateful.
Maybe I'm misinterpretting your question, but wouldn't re.sub be the best option?
Example: https://repl.it/DExs
Okay so two ways I did quickly! The second loop is definitely the way to go. It uses re.sub (as someone else commented too). It replaces with the lowercase search term bear in mind.
import re
FILE = open("testing.txt","r")
word="port"
#THIS LOOP IS CASE SENSITIVE
for line in FILE:
newline=line.replace(word,"<b><font color=\"red\">"+word+"</font></b>")
print newline
#THIS LOOP IS INCASESENSITIVE
for line in FILE:
pattern=re.compile(word,re.IGNORECASE)
newline = pattern.sub("<b><font color=\"red\">"+word+"</font></b>",line)
print newline
All diff tools I've found are just comparing line by line instead of char by char. Is there any library that gives details on single line strings? Maybe also a percentage difference, though I guess there are separate functions for that?
This algorithm diffs word-by-word:
http://github.com/paulgb/simplediff
available in Python and PHP. It can even spit out HTML formatted output using the <ins> and <del> tags.
I was looking for something similar recently, and came across wdiff. It operates on words, not characters, but is this close to what you're looking for?
What you could try is to split both strings up character by character into lines and then you can use diff on that. It's a dirty hack, but atleast it should work and is quite easy to implement.
Alternately you can split the string up into a list of chars in Python and use difflib. Check Python difflib reference
You can implement a simple Needleman–Wunsch algorithm. The pseudo code is available on Wikipedia: http://en.wikipedia.org/wiki/Needleman%E2%80%93Wunsch_algorithm
I’m a newbie in Python. I’m learning regexes, but I need help here.
Here comes the HTML source:
http://www.ptop.se
I’m trying to code a tool that only prints out http://ptop.se. Can you help me please?
If you're only looking for one:
import re
match = re.search(r'href=[\'"]?([^\'" >]+)', s)
if match:
print(match.group(1))
If you have a long string, and want every instance of the pattern in it:
import re
urls = re.findall(r'href=[\'"]?([^\'" >]+)', s)
print(', '.join(urls))
Where s is the string that you're looking for matches in.
Quick explanation of the regexp bits:
r'...' is a "raw" string. It stops you having to worry about escaping characters quite as much as you normally would. (\ especially -- in a raw string a \ is just a \. In a regular string you'd have to do \\ every time, and that gets old in regexps.)
"href=[\'"]?" says to match "href=", possibly followed by a ' or ". "Possibly" because it's hard to say how horrible the HTML you're looking at is, and the quotes aren't strictly required.
Enclosing the next bit in "()" says to make it a "group", which means to split it out and return it separately to us. It's just a way to say "this is the part of the pattern I'm interested in."
"[^\'" >]+" says to match any characters that aren't ', ", >, or a space. Essentially this is a list of characters that are an end to the URL. It lets us avoid trying to write a regexp that reliably matches a full URL, which can be a bit complicated.
The suggestion in another answer to use BeautifulSoup isn't bad, but it does introduce a higher level of external requirements. Plus it doesn't help you in your stated goal of learning regexps, which I'd assume this specific html-parsing project is just a part of.
It's pretty easy to do:
from BeautifulSoup import BeautifulSoup
soup = BeautifulSoup(html_to_parse)
for tag in soup.findAll('a', href=True):
print(tag['href'])
Once you've installed BeautifulSoup, anyway.
Don't use regexes, use BeautifulSoup. That, or be so crufty as to spawn it out to, say, w3m/lynx and pull back in what w3m/lynx renders. First is more elegant probably, second just worked a heck of a lot faster on some unoptimized code I wrote a while back.
this should work, although there might be more elegant ways.
import re
url='http://www.ptop.se'
r = re.compile('(?<=href=").*?(?=")')
r.findall(url)
John Gruber (who wrote Markdown, which is made of regular expressions and is used right here on Stack Overflow) had a go at producing a regular expression that recognises URLs in text:
http://daringfireball.net/2009/11/liberal_regex_for_matching_urls
If you just want to grab the URL (i.e. you’re not really trying to parse the HTML), this might be more lightweight than an HTML parser.
Regexes are fundamentally bad at parsing HTML (see Can you provide some examples of why it is hard to parse XML and HTML with a regex? for why). What you need is an HTML parser. See Can you provide an example of parsing HTML with your favorite parser? for examples using a variety of parsers.
In particular you will want to look at the Python answers: BeautifulSoup, HTMLParser, and lxml.
this regex can help you, you should get the first group by \1 or whatever method you have in your language.
href="([^"]*)
example:
amgheziName
result:
http://www.amghezi.com
There's tonnes of them on regexlib
Yes, there are tons of them on regexlib. That only proves that RE's should not be used to do that. Use SGMLParser or BeautifulSoup or write a parser - but don't use RE's. The ones that seems to work are extremely compliated and still don't cover all cases.
This works pretty well with using optional matches (prints after href=) and gets the link only. Tested on http://pythex.org/
(?:href=['"])([:/.A-z?<_&\s=>0-9;-]+)
Oputput:
Match 1. /wiki/Main_Page
Match 2. /wiki/Portal:Contents
Match 3. /wiki/Portal:Featured_content
Match 4. /wiki/Portal:Current_events
Match 5. /wiki/Special:Random
Match 6. //donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en
You can use this.
<a[^>]+href=["'](.*?)["']