使用 Python 正则表达式捕获具有相似模式的列

Question

I'm scraping a pdf using regex and Python. The patterns repeat through each column. I don't understand how to target each column of information separately.

Text string:

2000 2001 2002 2003\n
14,756 10,922 9,745 12,861\n
9,882 11,568 8,176 10,483\n
13,925 10,724 10,032 8,927\n

I need to return the data by year like:

[('2000', '14,756', '9,882', '13,925'),
('2001', '10,922', '11,568', '10,742'),
('2002', '9,745', '8,176', '10,032'),
('2003', '12,861', '10,483', '8,927')]

once I have the regex, I understand how to pull it from the page and put it into a df. I'm just not understanding how to target the columns separately. I just capture everything all at once.

Answer 1

I am afraid it is impossible to capture columns, but you can combine regex with matching the groups of the columns and transpose with zip .

(?:^|\n)([\d,]+)\s([\d,]+)\s([\d,]+)\s([\d,]+)(?:$|\n)

See how this regex works.

import re

text = """2000 2001 2002 2003
14,756 10,922 9,745 12,861
9,882 11,568 8,176 10,483
13,925 10,724 10,032 8,927"""

pattern = r"(?:^|\n)([\d,]+)\s([\d,]+)\s([\d,]+)\s([\d,]+)(?:$|\n)"
grouped = re.findall(pattern, text, flags=re.M)
columns = list(zip(*grouped))  # the expected result