On 08/25/2018 04:55 PM, Malcolm wrote:
I am trying to understand why regex is not extracting all of the
characters between two delimiters.
The complete string is the xmp IFD data extracted from a .CR2 image file.
I do have a work around, but it's messy and possibly not future proof.
Any insight greatly appreciated.
Malcolm
My test code is
import re
# environment # Python 3.6.5 (v3.6.5:f59c0932b4, Mar 28 2018, 17:00:18)
[MSC v.1900 64 bit (AMD64)] on win32 # extract of real data for test
purposes. This extract is repeated # the delimiters are <dc: and </dc:
extract =''' <dc:creator> <rdf:Seq> <rdf:li>abcdef zxcvb</rdf:li>
</rdf:Seq> </dc:creator> ''' # modify the test data modified_extract_1
=''' <dc:creator> <rdf:Seq> <rdf:li>abcdef zxcvb</rdf:li> </rdf:Seq>
</dc:creator> ''' # modify test data version 2 this works
modified_extract_2 =''' <dc:creator> <rdf:li>abcdef zxcvb</rdf:li>
</dc:creator> ''' re_pattern =r'( *<dc:.*</dc:)' print('extract',
re.search(re_pattern, extract, re.DOTALL))
# >>> s1 <_sre.SRE_Match object; span=(1, 89), match=' <dc:creator>\n
<rdf:Seq>\n <rdf:li>abcd> print('modified_extract_1',
re.search(re_pattern, modified_extract_1, re.DOTALL))
# >>> sre.SRE_Match object; span=(1, 70),
match='<dc:creator>\n<rdf:Seq>\n<rdf:li>abcdef zxcvb</rd>
print('modified_extract_2', re.search(re_pattern, modified_extract_2,
re.DOTALL))
# >>> s <_sre.SRE_Match object; span=(1, 49),
match='<dc:creator>\n<rdf:li>abcdef zxcvb</rdf:li>\n</dc> # NOTE the
missing ':' from the </dc I
Regexes are generally regarded as a bad way to parse XML data, and I
believe are provably unsuited in the general case (though can be beaten
into sufficiency in specific ones).
Use https://docs.python.org/3.6/library/xml.etree.elementtree.html
instead. Everything will just work. You'll be happier and more
productive, with a brighter smile and glossier coat.
--
Rob Gaddi, Highland Technology -- www.highlandtechnology.com
Email address domain is currently out of order. See above to fix.
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