This question showed how to replace a regex with another regex like this
$string = '"SIP/1037-00000014","SIP/CL-00000015","Dial","SIP/CL/61436523277,45"';
$$pattern = '["SIP/CL/(\d*),(\d*)",]';
$replacement = '"SIP/CL/\1|\2",';
$string = preg_replace($pattern, $replacement, $string);
print($string);
However, I couldn't adapt that pattern to solve my case where I want to remove the full stop that lies between 2 words but not between a word and a number:
text = 'this . is bad. Not . 820'
regex1 = r'(\w+)(\s\.\s)(\D+)'
regex2 = r'(\w+)(\s)(\D+)'
re.sub(regex1, regex2, text)
# Desired outcome:
'this is bad. Not . 820'
Basically I like to remove the . between the two alphabet words. Could someone please help me with this problem? Thank you in advance.
These expressions might be close to what you might have in mind:
\s[.](?=\s\D)
or
(?<=\s)[.](?=\s\D)
Test
import re
regex = r"\s[.](?=\s\D)"
test_str = "this . is bad. Not . 820"
print(re.sub(regex, "", test_str))
Output
this is bad. Not . 820
If you wish to explore/simplify/modify the expression, it's been
explained on the top right panel of
regex101.com. If you'd like, you
can also watch in this
link, how it would match
against some sample inputs.
Firstly, you can't really take PHP and apply it directly to Python, for obvious reasons.
Secondly, it always helps to specify which version of Python you're using as APIs change. Luckily in this instance, the API of re.sub has remained the same between Python 2.x and Python 3.
Onto your issue.
The second argument to re.sub is either a string or a function. If you pass in regex2 it'll just replace regex1 with the string contents of regex2, it won't apply regex2 as a regex.
If you want to use groups derived from the first regex (similar to your example, which is using \1 and \2 to extract the first and second matching group from the first regex), then you'd want to use a function, which takes a match object as its sole argument, which you could then use to extract matching groups and return them as part of the replacement string.
Related
I know that beautiful soup has a function to match classes based on regex that contains certain strings, based on a post here. Below is a code example from that post:
regex = re.compile('.*listing-col-.*')
for EachPart in soup.find_all("div", {"class" : regex}):
print EachPart.get_text()
Now, is it possible to do the opposite? Basically, find classes that do not contain a certain regex. In SQL language, it's like:
where class not like '%test%'
Thanks in advance!
This actually can be done by using Negative Lookahead
Negative Lookahead has the following syntax (?!«pattern») and matches if pattern does not match what comes before the current location in the input string.
In your case, you could use the following regex to match all classes that don’t contain listing-col- in their name:
regex = re.compile('^((?!listing-col-).)*$')
Here’s the pretty simple and straightforward explanation of this regex ^((?!listing-col-).)*$:
^ asserts position at start of a line
Capturing Group ((?!listing-col-).)*
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed
Negative Lookahead (?!listing-col-).
Assert that the Regex below does not match.
listing-col- matches the characters listing-col- literally (case sensitive)
. matches any character
$ asserts position at the end of a line
Also, you may find the https://regex101.com site useful
It will help you test your patterns and show you a detailed explanation of each step. It's your best friend in writing regular expressions.
One possible solution is utilizing regex directly.
You can refer to Regular expression to match a line that doesn't contain a word.
Or you can introduce a function to implement the logic and pass it to find_all as a parameter.
You can refer to https://beautiful-soup-4.readthedocs.io/en/latest/index.html?highlight=find_all#find-all
You can use css selector syntax with :not() pseudo class and * contains operator
data = [i.text() for i in soup.select('div[class]:not([class*="listing-col-"])')]
I am trying the following regex: https://regex101.com/r/5dlRZV/1/, I am aware, that I am trying with \author and not \maketitle
In python, I try the following:
import re
text = str(r'
\author{
\small
}
\maketitle
')
regex = [re.compile(r'[\\]author*|[{]((?:[^{}]*|[{][^{}]*[}])*)[}]', re.M | re.S),
re.compile(r'[\\]maketitle*|[{]((?:[^{}]*|[{][^{}]*[}])*)[}]', re.M | re.S)]
for p in regex:
for m in p.finditer(text):
print(m.group())
Python freezes, I am suspecting that this has something to do with my pattern, and the SRE fails.
EDIT: Is there something wrong with my regex? Can it be improved to actually work? Still I get the same results on my machine.
EDIT 2: Can this be fixed somehow so the pattern supports optional followed by ?: or ?= look-heads? So that one can capture both?
After reading the heading, "Parentheses Create Numbered Capturing Groups", on this site: https://www.regular-expressions.info/brackets.html, I managed to find the answer which is:
Besides grouping part of a regular expression together, parentheses also create a
numbered capturing group. It stores the part of the string matched by the part of
the regular expression inside the parentheses.
The regex Set(Value)? matches Set or SetValue.
In the first case, the first (and only) capturing group remains empty.
In the second case, the first capturing group matches Value.
I'm struggling to do multiline regex with multiple matches.
I have data separated by newline/linebreaks like below. My pattern matches each of these lines if i test it separately. How can i match all the occurrences (specifically numbers?
I've read that i could/should use DOTALL somehow (possibly with MULTILINE). This seems to match any character (newlines also) but not sure of any eventual side effects. Don't want to have it match an integer or something and give me malformed data in the end.
Any info on this would be great.
What i really need though, is some assistance in making this example code work. I only need to fetch the numbers from the data.
I used re.fullmatch when i only needed one specific match in a previous case and not entirely sure which function i should use now by the way (finditer, findall, search etc.).
Thank you for any and all help :)
data = """http://store.steampowered.com/app/254060/
http://www.store.steampowered.com/app/254061/
https://www.store.steampowered.com/app/254062
store.steampowered.com/app/254063
254064"""
regPattern = '^\s*(?:https?:\/\/)?(?:www\.)?(?:store\.steampowered\.com\/app\/)?([0-9]+)\/?\s*$'
evaluateData = re.search(regPattern, data, re.DOTALL | re.MULTILINE)
if evaluateString2 is not None:
print('do stuff')
else:
print('found no match')
import re
p = re.compile(ur'^\s*(?:https?:\/\/)?(?:www\.)?(?:store\.steampowered\.com\/app\/)?([0-9]+)\/?\s*$', re.MULTILINE)
test_str = u"http://store.steampowered.com/app/254060/\nhttp://www.store.steampowered.com/app/254061/\nhttps://www.store.steampowered.com/app/254062\nstore.steampowered.com/app/254063\n254064"
re.findall(p, test_str)
https://regex101.com/r/rC9rI0/1
this gives [u'254060', u'254061', u'254062', u'254063', u'254064'].
Are you trying to return those specific integers?
re.search stop at the first occurrence
You should use this intead
re.findall(regPattern, data, re.MULTILINE)
['254060', '254061', '254062', '254063', '254064']
Note: Search was not working for me (python 2.7.9). It just return the first line of data
/ has no special meaning so you do not have to escape it (and in not-raw strings you would have to escape every \)
try this
regPattern = r'^\s*(?:https?://)?(?:www\.)?(?:store\.steampowered\.com/app/)?([0-9]+)/?\s*$'
I need to build a program that can read multiple lines of code, and extract the right information from each line.
Example text:
no matches
one match <'found'>
<'one'> match <found>
<'three'><'matches'><'found'>
For this case, the program should detect <'found'>, <'one'>, <'three'>, <'matches'> and <'found'> as matches because they all have "<" and "'".
However, I cannot work out a system using regex to account for multiple matches on the same line. I was using something like:
re.search('^<.*>$')
But if there are multiple matches on one line, the extra "'<" and ">'" are taken as part of the .*, without counting them as separate matches. How do I fix this?
This works -
>>> r = re.compile(r"\<\'.*?\'\>")
>>> r.findall(s)
["<'found'>", "<'one'>", "<'three'>", "<'matches'>", "<'found'>"]
Use findall instead of search:
re.findall( r"<'.*?'>", str )
You can use re.findall and match on non > characters inside of the angle brackets:
>>> re.findall('<[^>]*>', "<'three'><'matches'><'found'>")
["<'three'>", "<'matches'>", "<'found'>"]
Non-greedy quantifier '?' as suggested by anubhava is also an option.
In Python, I am extracting emails from a string like so:
split = re.split(" ", string)
emails = []
pattern = re.compile("^[a-zA-Z0-9_\.-]+#[a-zA-Z0-9-]+.[a-zA-Z0-9-\.]+$");
for bit in split:
result = pattern.match(bit)
if(result != None):
emails.append(bit)
And this works, as long as there is a space in between the emails. But this might not always be the case. For example:
Hello, foo#foo.com
would return:
foo#foo.com
but, take the following string:
I know my best friend mailto:foo#foo.com!
This would return null. So the question is: how can I make it so that a regex is the delimiter to split? I would want to get
foo#foo.com
in all cases, regardless of punctuation next to it. Is this possible in Python?
By "splitting by regex" I mean that if the program encounters the pattern in a string, it will extract that part and put it into a list.
I'd say you're looking for re.findall:
>>> email_reg = re.compile(r'[a-zA-Z0-9_.-]+#[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+')
>>> email_reg.findall('I know my best friend mailto:foo#foo.com!')
['foo#foo.com']
Notice that findall can handle more than one email address:
>>> email_reg.findall('Text text foo#foo.com, text text, baz#baz.com!')
['foo#foo.com', 'baz#baz.com']
Use re.search or re.findall.
You also need to escape your expression properly (. needs to be escaped outside of character classes, not inside) and remove/replace the anchors ^ and $ (for example with \b), eg:
r"\b[a-zA-Z0-9_.+-]+#[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+\b"
The problem I see in your regex is your use of ^ which matches the start of a string and $ which matches the end of your string. If you remove it and then run it with your sample test case it will work
>>> re.findall("[A-Za-z0-9\._-]+#[A-Za-z0-9-]+.[A-Za-z0-9-\.]+","I know my best friend mailto:foo#foo.com!")
['foo#foo.com']
>>> re.findall("[A-Za-z0-9\._-]+#[A-Za-z0-9-]+.[A-Za-z0-9-\.]+","Hello, foo#foo.com")
['foo#foo.com']
>>>