How to avoid empty strings in pythong's regular expression function re.findAll?

Question

I use python's re module to recognize integers in a sentence. It produces empty strings as well. Any idea on how to remove those empty strings?

In [15]: myre="[0-9]*"

In [16]: re.findall(myre,"23")
Out[16]: ['23', '']

In [17]: re.findall(myre,"23 is a good number.")
Out[17]:
['23',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '',
 '']

This should answer your question: [Make regular expression not match empty string?](https://stackoverflow.com/questions/19620735/make-regular-expression-not-match-empty-string) — mkrieger1, Sep 18 '21 at 12:03

score 2 · Answer 1 · answered Sep 18 '21 at 12:03

2

You should be using [0-9]+ rather than [0-9]*; the latter matches against 0 or more (meaning that the digits are optional); +, however, matches against one or more.

answered Sep 18 '21 at 12:03

saedx1

984
6
20

score 1 · Accepted Answer · answered Sep 18 '21 at 12:11

1

The reason is your regex matches 0 or more occurences of digits. Change it to [0-9]+ or \d+ and try out.

answered Sep 18 '21 at 12:11

Bhagyesh Dudhediya

1,800
1
13
16

How to avoid empty strings in pythong's regular expression function re.findAll?

2 Answers2