83 – Extracting text data into a dict

83 – Extracting text data into a dict#

Regular expression matches from the module re have a method groupdict that allow you to create a dictionary with the named groups that your regular expression defines.

This is useful, for example, if you’re extracting data from structured text and want to convert it to a more convenient format (a dictionary).

Suppose you have a number of files for copyright-free books with a frontmatter header and the markdown contents:

---
title: Moby Dick
author: Herman Melville
---

[...]

You can define a regex pattern to extract the title and author information:

pattern = r"""(?x)
    ---\n
    title:\ (?P<title>.*?)\n
    author:\ (?P<author>.*?)\n
    ---"""

Then, you can use the module re and any of its functions to search/find text. If you get a match, you can use the method groupdict to create a dictionary with key/value pairs for every named group you defined. In the example above, that would be a dictionary with keys "title" and "author":

import re

print(
    re.match(pattern, text).groupdict()
)
# {'title': 'Moby Dick',
#  'author': 'Herman Melville'}