How Can I Correct My Python Regular Expressions Code for Analyzing Swallow Data?

[Schr0d1ng3r]

Homework Statement

This isn't really a homewrok/coursework question, but I didn't know where to put it. I'm trying to teach myself python over the summer and I seem to have got stuck on regular expressions. I want to read a .txt file with data for various kinds of swallows, laden/unlden, their airspeed velocities, and the date they were observed. Then, print only the ones which conform to the correct format. I managed to get the File I/O part to work, but the regex part doesn't.

2. The attempt at a solution

import re

# Open text file contining data
reader = open('C:\file.txt', 'r')
# Read all lines of data
data = reader.readlines()
# Print all lines of file
for line in data:
print line

# Close reader
reader.close()

print "\n\n\nShow Matches\n\n"

# Regular expression to find matching patterns in file
record = re.search((African|European) (Unladen|Laden) (\d{1,2}m/s) (\d{1-4}-\d{1,2}-\d{1,2})', data)
if record:
print match.search(1) + "\t" + match.search(2) + "\t" + match.search(3) + "\t" + match.search(4)

# Require input to close
x = raw_input("\n\nPress Enter")

 

[lofgran]

Hello there! It looks like you're on the right track with your code. Regular expressions can definitely be tricky, but with some practice and patience, you'll get the hang of it.

One thing I noticed is that your regular expression may need a few adjustments. The first thing is that you need to enclose your patterns in quotation marks, so it should look something like this: re.search('(African|European) (Unladen|Laden) (\d{1,2}m/s) (\d{1-4}-\d{1,2}-\d{1,2})', data). Also, in your second line of the regular expression, you have "match" instead of "record". It should be record.search(2) and so on.

Another thing to keep in mind is that regular expressions are case-sensitive, so make sure your patterns match the exact case of the data in your file.

I also recommend testing your regular expression with a smaller sample of data to make sure it's capturing the correct patterns before applying it to the entire file.

I hope this helps and good luck with your Python learning journey!