How to split but ignore separators in quoted strings, in python?

by

Most of the answers seem massively over complicated. You don’t need back references. You don’t need to depend on whether or not re.findall gives overlapping matches. Given that the input cannot be parsed with the csv module so a regular expression is pretty well the only way to go, all you need is to call re.split with a pattern that matches a field.

Note that it is much easier here to match a field than it is to match a separator:

import re
data = """part 1;"this is ; part 2;";'this is ; part 3';part 4;this "is ; part" 5"""
PATTERN = re.compile(r'''((?:[^;"']|"[^"]*"|'[^']*')+)''')
print PATTERN.split(data)[1::2]

and the output is:

['part 1', '"this is ; part 2;"', "'this is ; part 3'", 'part 4', 'this "is ; part" 5']

As Jean-Luc Nacif Coelho correctly points out this won’t handle empty groups correctly. Depending on the situation that may or may not matter. If it does matter it may be possible to handle it by, for example, replacing ';;' with ';<marker>;' where <marker> would have to be some string (without semicolons) that you know does not appear in the data before the split. Also you need to restore the data after:

>>> marker = ";!$%^&;"
>>> [r.replace(marker[1:-1],'') for r in PATTERN.split("aaa;;aaa;'b;;b'".replace(';;', marker))[1::2]]
['aaa', '', 'aaa', "'b;;b'"]

However this is a kludge. Any better suggestions?

More Related Contents:

  1. Take first some character of string but if particular character will come consider that character also
  2. How to extract numbers from a string in Python?
  3. Is it worth using Python’s re.compile?
  4. Extract part of a regex match
  5. Regular expression matching a multiline block of text
  6. What is the difference between re.search and re.match?
  7. regex for Twitter username
  8. Find shortest matches between two strings
  9. Matching Nested Structures With Regular Expressions in Python
  10. Python re.sub back reference not back referencing [duplicate]
  11. How to grab number after word in python
  12. Extract a string between double quotes
  13. Reuse part of a Regex pattern
  14. Find the indexes of all regex matches?
  15. RegEx Get string between two strings that has line breaks
  16. Python – re.findall returns unwanted result
  17. Why Does a Repeated Capture Group Return these Strings?
  18. Splitting out the output of ps using Python
  19. How to use regex to find all overlapping matches
  20. How can a recursive regexp be implemented in python?
  21. Python regular expression pattern * is not working as expected
  22. Split string at every position where an upper-case word starts
  23. FutureWarning: The default value of regex will change from True to False in a future version
  24. Why does this take so long to match? Is it a bug?
  25. Regex matching – why does this not match and return None?
  26. How to use str.contains() with multiple expressions in pandas dataframes
  27. match dates using python regular expressions
  28. How to Fix JSON Key Values without double-quotes?
  29. python regular expression across multiple lines
  30. How to use regex with optional characters in python?

Leave a Comment