regex – Tools for representing MongoDB regular expressions

New in version 2.7.

Tools for representing MongoDB regular expressions.

class bson.regex.Regex(pattern: bson.regex._T, flags: Union[str, int] = 0)

BSON regular expression data.

This class is useful to store and retrieve regular expressions that are incompatible with Python’s regular expression dialect.

Parameters
  • pattern: string

  • flags: (optional) an integer bitmask, or a string of flag characters like “im” for IGNORECASE and MULTILINE

classmethod from_native(regex: Pattern[bson.regex._T]) bson.regex.Regex[bson.regex._T]

Convert a Python regular expression into a Regex instance.

Note that in Python 3, a regular expression compiled from a str has the re.UNICODE flag set. If it is undesirable to store this flag in a BSON regular expression, unset it first:

>>> pattern = re.compile('.*')
>>> regex = Regex.from_native(pattern)
>>> regex.flags ^= re.UNICODE
>>> db.collection.insert_one({'pattern': regex})
Parameters
  • regex: A regular expression object from re.compile().

Warning

Python regular expressions use a different syntax and different set of flags than MongoDB, which uses PCRE. A regular expression retrieved from the server may not compile in Python, or may match a different set of strings in Python than when used in a MongoDB query.

try_compile() Pattern[bson.regex._T]

Compile this Regex as a Python regular expression.

Warning

Python regular expressions use a different syntax and different set of flags than MongoDB, which uses PCRE. A regular expression retrieved from the server may not compile in Python, or may match a different set of strings in Python than when used in a MongoDB query. try_compile() may raise re.error.