Detailed explanation of nested instances using regular expressions in python, python Regular Expressions

Detailed explanation of nested instances using regular expressions in python, python Regular Expressions

Detailed description of nested instances using regular expressions in python

Because the group itself is a complete regular expression, you can nest the group in other groups to build more complex expressions. The following is an example of group nesting:

# Python 3.6 # Cai junsheng # http://blog.csdn.net/caimouse/article/details/51749579 # import re def test_patterns (text, patterns): "" Given source text and a list of patterns, look for matches for each pattern within the text and print them to stdout. "# Look for each pattern in the text and print the results for pattern, desc in patterns: print ('{! R} ({}) \ n'. format (pattern, desc) print ('{! R }'. format (text) for match in re. finditer (pattern, text): s = match. start () e = match. end () prefix = ''* (s) print ('{}{! R }{}'. format (prefix, text [s: e], ''* (len (text)-e), end ='',) print (match. groups () if match. groupdict (): print ('{}{}'. format (''* (len (text)-s), match. groupdict (),) print () return

Example:

# Python 3.6 # Cai junsheng # http://blog.csdn.net/caimouse/article/details/51749579 # from re_test_patterns_groups import test_patterns ('ababbba ', [(r 'a (a *) (B *))', 'A followed by 0-n a and 0-n B ')],)

 

The output is as follows:

'a((a*)(b*))' (a followed by 0-n a and 0-n b) 'abbaabbba' 'abb'    ('bb', '', 'bb')   'aabbb'  ('abbb', 'a', 'bbb')     'a' ('', '', '')

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