CODEWITHSUNDEEP
pythonregexpython-2.7
Neomind
Neomind

Reputation: 513

Python re.findall

I'm trying to retrieve all the tags containing a 'name' field, and then treat the whole sentence plus the name. This is the test code I have:

sourceCode = '<dirtfields name="one" value="stuff">\n<gibberish name="two"\nwewt>'
namesGroup = re.findall('<.*name="(.*?)".*>', sourceCode, re.IGNORECASE | re.DOTALL)

for name in namesGroup:
    print name

Which output is:

two

And the output I am trying to look for would be

['<dirtfields name="one" value="stuff">', 'one']
['<gibberish name="two"\nwewt>', 'two']

EDIT: Found a way to do it, thanks to doublesharp for the cleaner way to get the 'name' value.

namesGroup = re.findall(r'(<.*?name="([^"]*)".*?>)', sourceCode, re.IGNORECASE | re.DOTALL)

Which will output:

('<dirtfields name="one" value="stuff">', 'one')
('<gibberish name="two"\nwewt>', 'two')

Upvotes: 3

Views: 8780

Answers (4)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89547

It is a pattern that allows escaped quotes inside the value and that avoid (for performance reasons) lazy quantifiers. This is the reason why it's a bit long but more waterproof:

myreg = re.compile(r"""
    < (?: [^n>]+ | \Bn | n(?!ame\s*=) )+   # begining of the tag 
                                           # until the name attribute
    name \s* = \s* ["']?                   # attribute until the value
    ( (?: [^\s\\"']+ | \\{2} | \\. )* )    # value
    [^>]*>                                 # end of the tag
""", re.X | re.I | re.S)

namesGroup = myreg.findall(sourceCode)

However using BS4 is a nice solution for your case.

Upvotes: 0

B.Mr.W.
B.Mr.W.

Reputation: 19628

Clearly you are dealing with HTML or XML file and looking for some values of specific attribute.

You will make a directional mistake if you keep working with regular expressions instead of a legit text parser.

Like BeautifulSoup4, the one I like the most, here is an very brief example of how to use it:

from bs4 import BeautifulSoup

sourceCode = '<dirtfields name="one" value="stuff">\n<gibberish name="two"\nwewt>'

soup = BeautifulSoup(sourceCode)
print soup.prettify()
print '------------------------'
for tag in soup.find_all():
    if tag.has_key('name'):
        print tag, tag['name']

The output looks a bit ugly now (the output is even wrong), but this shows that how beautifulsoup will auto fix your broken html and easily locate the attribute you want. 

<html>
 <body>
  <dirtfields name="one" value="stuff">
   <gibberish name="two" wewt="">
   </gibberish>
  </dirtfields>
 </body>
</html>
------------------------
<dirtfields name="one" value="stuff">
<gibberish name="two" wewt=""></gibberish></dirtfields> one
<gibberish name="two" wewt=""></gibberish> two

Add Beautifulsoup to your favorite Stackoverflow tags and you will be surprise how good it is and how many people are doing the same thing as you with a more powerful tool!

Upvotes: 2

doublesharp
doublesharp

Reputation: 27599

Your regex is a bit off - you are matching too much (all the way to the last >). Since you just need to values between the double quotes after name= use the following pattern:

name="([^"]*)"
  • name=" matches the first part of the attribute you are looking for
  • ([^"]*) creates a grouped match based on any characters that are not a double quote
  • " matches the double quote after the name attribute value.

And your code would look like this (it's good form to include an r before your pattern):

namesGroup = re.findall(r'name="([^"]*)"', sourceCode, re.IGNORECASE)

Upvotes: 4

OGHaza
OGHaza

Reputation: 4795

(?<=name=")[^"]*

If you wanted to match only the name without having a capture group, you could use:

re.findall(r'(?<=name=")[^"]*', sourceCode, re.IGNORECASE )

Output: ['one', 'two']

Of course capture groups are an equally acceptable solution.

Upvotes: 2

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