I'm struggling a bit on how to extract (i.e. assign to variable) a string based on a regex. I have the regex worked out -- I tested on regexpal. But I'm lost on how I actually implement that in Python. My regex string is:
http://jenkins.mycompany.com/job/[^\s]+
What I want to do is take string and if there's a pattern in there that matches the regex, put that entire "pattern" into a variable. So for example, given the following string:
There is a problem with http://jenkins.mycompany.com/job/app/4567. We should fix this.
I want to extract http://jenkins.mycompany.com/job/app/4567and assign it a variable. I know I'm supposed to use re but I'm not sure if I want re.match or re.search and how to get what I want. Any help or pointers would be greatly appreciated.
import re
p = re.compile('http://jenkins.mycompany.com/job/[^\s]+')
line = 'There is a problem with http://jenkins.mycompany.com/job/app/4567. We should fix this.'
result = p.search(line)
print result.group(0)
Output:
http://jenkins.mycompany.com/job/app/4567.
Try the first found match in the string, using the re.findall method to select the first match:
re.findall(pattern_string, input_string)[0] # pick the first match that is found
Related
I am new to regexes.
I have the following string : \n(941)\n364\nShackle\n(941)\nRivet\n105\nTop
Out of this string, I want to extract Rivet and I already have (941) as a string in a variable.
My thought process was like this:
Find all the (941)s
filter the results by checking if the string after (941) is followed by \n, followed by a word, and ending with \n
I made a regex for the 2nd part: \n[\w\s\'\d\-\/\.]+$\n.
The problem I am facing is that because of the parenthesis in (941) the regex is taking 941 as a group. In the 3rd step the regex may be wrong, which I can fix later, but 1st I needed help in finding the 2nd (941) so then I can apply the 3rd step on that.
PS.
I know I can use python string methods like find and then loop over the searches, but I wanted to see if this can be done directly using regex only.
I have tried the following regex: (?:...), (941){1} and the make regex literal character \ like this \(941\) with no useful results. Maybe I am using them wrong.
Just wanted to know if it is possible to be done using regex. Though it might be useful for others too or a good share for future viewers.
Thanks!
Assuming:
You want to avoid matching only digits;
Want to match a substring made of word-characters (thus including possible digits);
Try to escape the variable and use it in the regular expression through f-string:
import re
s = '\n(941)\n364\nShackle\n(941)\nRivet\n105\nTop'
var1 = '(941)'
var2 = re.escape(var1)
m = re.findall(fr'{var2}\n(?!\d+\n)(\w+)', s)[0]
print(m)
Prints:
Rivet
If you have text in a variable that should be matched exactly, use re.escape() to escape it when substituting into the regexp.
s = '\n(941)\n364\nShackle\n(941)\nRivet\n105\nTop'
num = '(941)'
re.findall(rf'(?<=\n{re.escape(num)}\n)[\w\s\'\d\-\/\.]+(?=\n)', s)
This puts (941)\n in a lookbehind, so it's not included in the match. This avoids a problem with the \n at the end of one match overlapping with the \n at the beginning of the next.
I need to extract only the part 0000520621 from the string nmg-22373-0000520621-001-010000520621.
I would like to use regular expressions in python for this task.
Can you help me in doing so?
You don't need a regexp to get the third member of a list. Just split your string by the minus character and pick it's third member.
test = 'nmg-22373-0000520621-001-010000520621'
test.split('-')[2]
my_string = 'nmg-22373-0000520621-001-010000520621'
expected = re.search('22373-(.+?)-001',l)
if expected:
print expected.group(1)
In the following regex r"\g<NAME>\w+", I would like to know that a group named NAME must be used for replacements corresponding to a match.
Which regex matches the wrong use of \g<...> ?
For example, the following code finds any not escaped groups.
p = re.compile(r"(?:[^\\])\\g<(\w+)>")
for m in p.finditer(r"\g<NAME>\w+\\g<ESCAPED>"):
print(m.group(1))
But there is a last problem to solve. How can I manage cases of \g<WRONGUSE\> and\g\<WRONGUSE> ?
As far as I am aware, the only restriction on named capture groups is that you can't put metacharacters in there, such as . \, etc...
Have you come across some kind of problem with named capture groups?
The regex you used, r"illegal|(\g<NAME>\w+)" is only illegal because you referred to a backreference without it being declared earlier in the regex string. If you want to make a named capture group, it is (?P<NAME>regex)
Like this:
>>> import re
>>> string = "sup bro"
>>> re.sub(r"(?P<greeting>sup) bro", r"\g<greeting> mate", string)
'sup mate'
If you wanted to do some kind of analysis on the actual regex string in use, I don't think there is anything inside the re module which can do this natively.
You would need to run another match on the string itself, so, you would put the regex into a string variable and then match something like \(\?P<(.*?)>\) which would give you the named capture group's name.
I hope that is what you are asking for... Let me know.
So, what you want is to get the string of the group name, right?
Maybe you can get it by doing this:
>>> regex = re.compile(r"illegal|(?P<group_name>\w+)")
>>> regex.groupindex
{'group_name': 1}
As you see, groupindex returns a dictionary mapping the group names and their position in the regex. Having that, it is easy to retrieve the string:
>>> # A list of the group names in your regex:
... regex.groupindex.keys()
['group_name']
>>> # The string of your group name:
... regex.groupindex.keys()[0]
'group_name'
Don't know if that is what you were looking for...
Use a negative lookahead?
\\g(?!<\w+>)
This search for any g not followed by <…>, thus a "wrong use".
Thanks to all the comments, I have this solution.
# Good uses.
p = re.compile(r"(?:[^\\])\\g<(\w+)>")
for m in p.finditer(r"</\g\<at__tribut1>\\g<notattribut>>"):
print(m.group(1))
# Bad uses.
p = re.compile(r"(?:[^\\])\\g(?!<\w+>)")
if p.search(r"</\g\<at__tribut1>\\g<notattribut>>"):
print("Wrong use !")
This might be trivial for those in this forum, but I ended up debugging this for the entire day. I have a python script running, but the issue boils down to this:
import re
spice="IN_N1"
rtl="IN_N13"
re.match(spice,rtl)
This returns a match object. Python seems to match the string IN_N1 anywhere in the second string and returns a match. I want it to compare the entire string and return a no match for this case. In other words, I want the above to be a match only if spice="IN_N13". It would be great if someone can suggest a solution.
Thanks!
Your Python regexp is interpreted as IN_N1.*
Change your pattern to IN_N1$ and it should work.
However consider Aleksanders comment ;)
//Edit: fixed regexp to consider comment
#!/usr/bin/python
import re
str = raw_input("String containing email...\t")
match = re.search(r'[\w.-]+#[\w.-]+', str)
if match:
print match.group()
it's not the most complicated code, and i'm looking for a way to get ALL of the matches, if it's possible.
It sounds like you want re.findall():
findall(pattern, string, flags=0)
Return a list of all non-overlapping matches in the string.
If one or more groups are present in the pattern, return a
list of groups; this will be a list of tuples if the pattern
has more than one group.
Empty matches are included in the result.
As far as the actual regular expression for identifying email addresses goes... See this question.
Also, be careful using str as a variable name. This will hide the str built-in.
I guess that re.findall is what you're looking for.
You should give a try for find() or findall()
findall() matches all occurrences of a
pattern, not just the first one as
search() does. For example, if one was
a writer and wanted to find all of the
adverbs in some text, he or she might
use findall()
http://docs.python.org/library/re.html#finding-all-adverbs
You don't use raw_input in the way you used. Just use raw_input to get the input from the console.
Don't override built-in's such as str. Use a meaningful name and assign it a whole string value.
Also it is a good idea many a times to compile your pattern have it a Regex object to match the string against. (illustrated in the code)
I just realized that a complete regex to match an email id exactly as per RFC822 could be a pageful otherwise this snippet should be useful.
import re
inputstr = "something#exmaple.com, 121#airtelnet.com, ra#g.net, etc etc\t"
mailsrch = re.compile(r'[\w\-][\w\-\.]+#[\w\-][\w\-\.]+[a-zA-Z]{1,4}')
matches = mailsrch.findall(inputstr)
print matches