How to parse this text file with regexp, in Python?

Question

I need to parse text file which contains logins and id of users

+----+---------------+---------------+
| Id | Login         | Name          |
+----+---------------+---------------+
| 1  | admin         | admin         |
| 2  | admin2        | admin2        |
| 3  | ekaterina     | Ekaterina     |
| 4  | commarik      | commarik      |
| 5  | basildrescher | BasilDrescher |
| 6  | danielalynn   | DanielaLynn   |
| 7  | rosez13yipfj  | RoseZ13yipfj  |
| 8  | veolanoyes    | VeolaNoyes    |
| 9  | angel         | Angel         |
| 10 | michalea44    | MichaleA44    |
+----+---------------+---------------+

So I use re, like this:

import re
fh = open('test1.txt')
lines = fh.readlines()
for line in lines:
        #print line
        p = re.compile(r"|(.*?)|")
        m2 = p.search(line)
        if m2:
                print m2.group(0)

The problem is that I can't get needed result! I've tried various combinations with spaces and tabs, but it didn't work. I solved this with split(), but I still want to understand where I am wrong. Any help would be appreciated. Thank you!

Answer 1

You have multiple errors:

• The | is not escaped
• You only have one group, so you are extracting only the first column.

The regex should be like this:

\|(.*?)\|(.*?)\|(.*?)\|

You can see a demo here.

Answer 2

If you dont expect fancy data, you can just use word chars and digits.

r"([\d\w]+)

Sample usage below

In [27]: data = """+----+---------------+---------------+
....:     | Id | Login         | Name          |
....:     +----+---------------+---------------+
....:     | 1  | admin         | admin         |
....:     | 2  | admin2        | admin2        |
....:     | 3  | ekaterina     | Ekaterina     |
....:     | 4  | commarik      | commarik      |
....:     | 5  | basildrescher | BasilDrescher |
....:     | 6  | danielalynn   | DanielaLynn   |
....:     | 7  | rosez13yipfj  | RoseZ13yipfj  |
....:     | 8  | veolanoyes    | VeolaNoyes    |
....:     | 9  | angel         | Angel         |
....:     | 10 | michalea44    | MichaleA44    |
....:     +----+---------------+---------------+"""

In [32]: matches = re.findall(r"([\d\w]+)", data)
In [36]: matches
Out[36]: ['Id', 'Login', 'Name', '1', 'admin', 'admin', '2', 'admin2', 'admin2', '3', 'ekaterina', 'Ekaterina', '4', 'commarik', 'commarik', '5', 'basildrescher', 'BasilDrescher', '6', 'danielalynn', 'DanielaLynn', '7', 'rosez13yipfj', 'RoseZ13yipfj', '8', 'veolanoyes', 'VeolaNoyes', '9', 'angel', 'Angel', '10', 'michalea44', 'MichaleA44']

Answer 3

| is a special character in regular expressions for "or"ing two expressions together. You need to escape it as \| to match the actual character. Also, search() will find one match. You may want to look through other methods such as findall.

Answer 4

Try using this regex to capture each individual line as a separate capture group, according to syntax:

\|\s*([0-9]+)\s*\|\s*([\w]+)\s*\|\s*([\w]+)\s*\|

Or, use this one to capture the same way you're trying above (which will also get the headers):

\|\s*(.*?)\s*\|\s*(.*?)\s*\|\s*(.*?)\s*\|

Here's a demo of the first.

As two other people have already said, you didn't escape your pipe character, which was messing up.

Also, you weren't taking into account whitespace on the edges of the words, so I added the \s regex pattern and kept that outside of the captured group to better what you get out.

Answer 5

Yes, something like the below would work;

import re
fh = open('test1.txt')
lines = fh.readlines()
for line in lines[2:]:
    p = re.compile(r"\|(?P<id>.*)\|(?P<login>.*)\|(?P<name>.*)\|")
    if p.search(line):
        id = re.match(p, line).group('id')
        login = re.match(p, line).group('login')
        name = re.match(p, line).group('name')
        print id.strip(),login.strip(),name.strip()