CODEWITHSUNDEEP
pythonregex
Ryan
Ryan

Reputation: 11

Python Re: tested regex patterns returning no matches

Using the python below I am trying to find specific headings with a markdown file

import re

source_file = open('readme.md')

#Defines variables containing the headings as Regex searches

product_name = re.compile('(?mi)^#+[^\S\n]product.*name')
product_version = re.compile('(?mi)^#+[^\S\n]product.*version')
product_description = re.compile('(?mi)^#+[^\S\n]product.*description')

#Adds the required headings to a list
headings = [product_name, product_version, product_description]

#Opens the readme, searches for the specified headings, then uses print_section to print the content under the headings
with open('readme.md') as file:
    for x in headings:
        content = x.search(file.read()).group(0)
        print(content)

The readme.md file contains the following placeholder text

# Product Name
Test Product
## Product Version
0.01
## Product Description
A short overview of what this product is; what it does; and what its intended use case is
# Specifications
## Networking
the quick brown fox jumped over the lazy dog
## Data Usage
This is line one of the sample
This is line two of the sample

The response I get from running this file is:

# Product Name
Traceback (most recent call last):
  File "sample.py", line 16, in <module>
    content = x.search(file.read()).group(0)
AttributeError: 'NoneType' object has no attribute 'group'

So I think there is an issue with the 2nd and 3rd Regex patterns. However in regex testers they appear to match properly. I can't really spot any differences between these patterns and the first which is successful, I've even tried swapping the ordering of the content in the markdown file, and still only product_name matches.

Upvotes: 1

Views: 31

Answers (1)

ilyankou
ilyankou

Reputation: 1329

Read the file only once, and search it:

with open('readme.md') as file:
    f = file.read()
    for x in headings:
        content = x.search(f).group(0)
        print(content)

As soon as Python read() reaches the end of the file (basically after your first iteration), it will keep returning an empty string. And you keep getting NoneType error because you search an empty string.

Upvotes: 1

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